OSA's Digital Library

Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 20, Iss. 4 — Feb. 13, 2012
  • pp: 3424–3433
« Show journal navigation

Optical features of a LiF crystal soft x-ray imaging detector irradiated by free electron laser pulses

Tatiana Pikuz, Anatoly Faenov, Yuji Fukuda, Masaki Kando, Paul Bolton, Alexander Mitrofanov, Alexander Vinogradov, Mitsuru Nagasono, Haruhiko Ohashi, Makina Yabashi, Kensuke Tono, Yashinori Senba, Tadashi Togashi, and Tetsuya Ishikawa  »View Author Affiliations


Optics Express, Vol. 20, Issue 4, pp. 3424-3433 (2012)
http://dx.doi.org/10.1364/OE.20.003424


View Full Text Article

Acrobat PDF (1112 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

Optical features of point defects photoluminescence in LiF crystals, irradiated by soft X-ray pulses of the Free Electron Laser with wavelengths of 17.2 – 61.5 nm, were measured. We found that peak of photoluminescence spectra lies near of 530 nm and are associated with emission of F3+ centers. Our results suggest that redistribution of photoluminescence peak intensity from the red to the green part of the spectra is associated with a shortening of the applied laser pulses down to pico - or femtosecond durations. Dependence of peak intensity of photoluminescence spectra from the soft X-ray irradiation fluence was measured and the absence of quenching phenomena, even at relatively high fluencies was found, which is very important for wide applications of LiF crystal X-ray imaging detectors.

© 2012 OSA

1. Introduction

Point defects [1

1. J. H. Schulman and W. D. Compton, Color Centers in Solids, (Oxford, 1962).

] in lithium fluoride (LiF) crystals have permanently attracted wide attention due to both fundamental and application interests, especially in such fields as electron and gamma – ray dosimetry [2

2. W. L. McLaughlin, A. C. Lucas, B. M. Kapsar, and A. Miller, “Electron and gamma-ray dosimetry using radiation induced color centers in LiF,” Radiat. Phys. Chem. 14, 467–480 (1979).

], active medium in light emitting devices for optoelectronics and integrated optics [3

3. T. Kurobori, T. Kitao, Y. Hirose, K. Kawamura, D. Takamizu, M. Hirano, and H. Hosono, “Laser-active colour centers with functional peridodic structures in LiF fabricated by two interfering femtosecond laser pulses,” Radiat. Meas. 38(4-6), 759–762 (2004). [CrossRef]

5

5. F. Bonfigli, A. Faenov, F. Flora, T. Marolo, R. M. Montereali, E. Nichelatti, T. Pikuz, L. Reale, and G. Baldacchini, “Point defects in lithium fluoride films for micro-radiography, X-Ray microscopy and photonic applications,” Phys. Status Solidi 202(2), 250–255 (2005) (a). [CrossRef]

]. Recently, a new field of application of optically stimulated luminescence of color centers (CCs) in lithium fluoride (LiF) crystals was proposed - using them for high-performance soft X-ray [6

6. G. Baldacchini, F. Bonfigli, F. Flora, R. M. Montereali, D. Murra, E. Nichelatti, A. Ya. Faenov, and T. A. Pikuz, “High-contrast photoluminiscent patterns in lithium fluoride crystals produced by soft X-rays from a laser-plasma source,” Appl. Phys. Lett. 80(25), 4810–4812 (2002). [CrossRef]

15

15. S. V. Gasilov, A. Ya. Faenov, T. A. Pikuz, Y. Fukuda, M. Kando, T. Kawachi, I. Yu. Skobelev, H. Daido, Y. Kato, and S. V. Bulanov, “Wide-field-of-view phase-contrast imaging of nanostructures with a comparatively large polychromatic soft x-ray plasma source,” Opt. Lett. 34(21), 3268–3270 (2009). [CrossRef] [PubMed]

], or for hard X-ray [16

16. S. Almaviva, F. Bonfigli, I. Franzini, A. Lai, R. M. Montereali, D. Pelliccia, A. Cedola, and S. Lagomarsino, “Hard x-ray contact microscopy with 250 nm spatial resolution using a LiF film detector and a tabletop microsource,” Appl. Phys. Lett. 89(5), 054102 (2006). [CrossRef]

], or for neutron [17

17. M. Matsubayashi, A. Faenov, T. Pikuz, Y. Fukuda, and Y. Kato, “Neutron imaging of micron-size structures by color center formation in LiF crystals,” Nucl. Instrum. Meth. A 622(3), 637–641 (2010). [CrossRef]

] imaging - and promising results were obtained. It was found in all of the above-mentioned investigations that point defects or, as they are also called CCs, are produced sufficiently easily under interaction of particles or with photons with LiF crystal. Such CCs could be hosted in LiF at room temperature for a very long time and then under excitation by UV radiation the CCs would emit in the visible spectral range.

As it was demonstrated in [5

5. F. Bonfigli, A. Faenov, F. Flora, T. Marolo, R. M. Montereali, E. Nichelatti, T. Pikuz, L. Reale, and G. Baldacchini, “Point defects in lithium fluoride films for micro-radiography, X-Ray microscopy and photonic applications,” Phys. Status Solidi 202(2), 250–255 (2005) (a). [CrossRef]

, 9

9. G. Baldacchini, S. Bollanti, F. Bonfigli, F. Flora, P. Di Lazzaro, A. Lai, T. Marolo, R. M. Montereali, D. Murra, A. Faenov, T. Pikuz, E. Nichelatti, G. Tomassetti, A. Reale, L. Reale, A. Ritucci, T. Limongi, L. Palladino, M. Francucci, S. Martellucci, and G. Petrocelli, “Soft x-ray submicron imaging detector based on point defects in LiF,” Rev. Sci. Instrum. 76(11), 113104 (2005). [CrossRef]

, 18

18. T. Kurobori, K. Kawamura, M. Hirano, and H. Hosono, “Simultaneous fabrication of laser-active colour centers and permanent microgratings in lithium fluoride by a single femtosecond pulse,” J. Phys- Condens Mat. 15, 399–405 (2003).

] among various aggregates of CCs produced in LiF crystals, that only F2 and F3+ have practical relevance for imaging applications. They have almost overlapped broad absorption bands at about 450 nm (M band). It means that they can be simultaneously excited by a single pumping wavelength. Moreover, they mainly contribute to visible luminescence in two very well separated broad emission bands in the green (F3+) and in the red (F2) spectral ranges. For different imaging applications of LiF crystals, detailed investigations of their optical properties from irradiation parameters are needed. Particular interest for imaging application of LiF crystals is connected with measurements of its photoluminescence (PL) spectrum and dependence of PL intensity response on the fluence of LiF irradiation.

Another existing uncertainty in the optical properties of LiF luminescence is connected with the behavior of LiF crystal PL response to a soft X-ray fluence. Indeed, in the case of irradiation of LiF crystal by soft X-ray beams with of ~10th nanosecond pulse durations, it was measured [5

5. F. Bonfigli, A. Faenov, F. Flora, T. Marolo, R. M. Montereali, E. Nichelatti, T. Pikuz, L. Reale, and G. Baldacchini, “Point defects in lithium fluoride films for micro-radiography, X-Ray microscopy and photonic applications,” Phys. Status Solidi 202(2), 250–255 (2005) (a). [CrossRef]

, 9

9. G. Baldacchini, S. Bollanti, F. Bonfigli, F. Flora, P. Di Lazzaro, A. Lai, T. Marolo, R. M. Montereali, D. Murra, A. Faenov, T. Pikuz, E. Nichelatti, G. Tomassetti, A. Reale, L. Reale, A. Ritucci, T. Limongi, L. Palladino, M. Francucci, S. Martellucci, and G. Petrocelli, “Soft x-ray submicron imaging detector based on point defects in LiF,” Rev. Sci. Instrum. 76(11), 113104 (2005). [CrossRef]

, 20

20. F. Bonfigli, F. Flora, I. Franzini, E. Nichelatti, and R. M. Montereali, “Optical characterization of a soft X-ray imaging detector based on photoluminiscent point defects in lithium fluoride thin layer,” J. Lumin. 129(12), 1964–1967 (2009). [CrossRef]

] that growth of PL intensity follows a square root law with the increase of soft X-ray fluence. On the contrary [10

10. F. Calegari, G. Valentini, C. Vozzi, E. Benedetti, J. Cabanillas-Gonzalez, A. Faenov, S. Gasilov, T. Pikuz, L. Poletto, G. Sansone, P. Villoresi, M. Nisoli, S. De Silvestri, and S. Stagira, “Elemental sensitivity in soft x-ray imaging with a laser-plasma source and a color center detector,” Opt. Lett. 32(17), 2593–2595 (2007). [CrossRef] [PubMed]

, 13

13. A. Ya. Faenov, Y. Kato, M. Tanaka, T. A. Pikuz, M. Kishimoto, M. Ishino, M. Nishikino, Y. Fukuda, S. V. Bulanov, and T. Kawachi, “Submicrometer-resolution in situ imaging of the focus pattern of a soft x-ray laser by color center formation in LiF crystal,” Opt. Lett. 34(7), 941–943 (2009). [CrossRef] [PubMed]

], when LiF crystals were irradiated by femtosecond or picosecond soft X-ray pulses, the measured PL intensity dependence from fluence was practically linear.

In order to resolve these above mentioned contradictions, it is necessary to measure PL intensity as well as spectra of CCs produced in LiF crystals by its irradiation with the source, which could exclude multiphoton ionization processes. This means that such photon source should deliver simultaneously ultra-short pulses with the energy of photons exceeding the 14 eV band-gap of LiF crystal and in a very wide range of soft X-ray fluence.

In this paper we are providing the first measurements of optical features of PL of CCs in LiF crystals, irradiated by monochromatic, femtosecond soft X-ray pulses in the spectral range of 17.2 – 61.5 nm. Flexibility and high repetition rate of self-amplified spontaneous emission-free electron laser (SASE-FEL) facility used in our experiments, allowed irradiating LiF crystals in a very wide range of soft X-ray fluencies from 10 μJ/cm2 up to 250 mJ/cm2. A new method is proposed for determination of the CCs PL response curve of the LiF - crystal imaging detector the soft X-ray fluence, based on the comparison of measured and calculated intensities of diffracted on the mesh SASE-FEL beam, while the measured data is compared with the data obtained with traditional methods.

2. Experimental setup

The experiment with the SASE-FEL facility was performed at the SPring-8 Compact SASE Source (SCSS). This system can provide laser pulses in the soft X-ray region (51-62 nm) [21

21. . Shintake, H. Tanaka, T. Hara, T. Tanaka, K. Togawa, M. Yabashi, Y. Otake, Y. Asano, T. Bizen, T. Fukui, S. Goto, A. Higashiya, T. Hirono, N. Hosoda, T. Inagaki, S. Inoue, M. Ishii, Y. Kim, H. Kimura, M. Kitamura, T. Kobayashi, H. Maesaka, T. Masuda, S. Matsui, T. Matsushita, X. Maréchal, M. Nagasono, H. Ohashi, T. Ohata, T. Ohshima, K. Onoe, K. Shirasawa, T. Takagi, S. Takahashi, M. Takeuchi, K. Tamasaku, R. Tanaka, Y. Tanaka, T. Tanikawa, T. Togashi, S. Wu, A. Yamashita, K. Yanagida, C. Zhang, H. Kitamura, and T. Ishikawa, “A compact free-electron laser for generating coherent radiation in the extreme ultraviolet region,” Nat. Photonics 2(9), 555–559 (2008). [CrossRef]

, 22

22. M. Kato, N. Saito, T. Tanaka, Y. Morishita, H. Kimura, H. Ohashi, M. Nagasono, M. Yabashi, K. Tono, T. Togashi, A. Higashiya, and T. Ishikawa, “Pulse energy of the extreme - ultraviolet free - electron laser at SPring-8 determined using a cryogenic radiometer,” Nucl. Instrum. Meth. A 612(1), 209–211 (2009). [CrossRef]

]. Using additional filtering it was also possible to select more short soft X-ray radiation generated by 3d harmonic of the main laser pulse [22

22. M. Kato, N. Saito, T. Tanaka, Y. Morishita, H. Kimura, H. Ohashi, M. Nagasono, M. Yabashi, K. Tono, T. Togashi, A. Higashiya, and T. Ishikawa, “Pulse energy of the extreme - ultraviolet free - electron laser at SPring-8 determined using a cryogenic radiometer,” Nucl. Instrum. Meth. A 612(1), 209–211 (2009). [CrossRef]

]. In this case, the FEL energy reached ~1.5% value of the main pulse energy. In our experiments, FEL operated at wavelengths of 61.5 nm, 52 nm and their 3d harmonics (20.5 nm and ~17.3 nm, respectively). In the case of LiF crystal irradiation by 1 - 30 shots, we have used a single shot mode of SASE-FEL and in the case of accumulation, up to 24 000 shots repetition (10 Hz) mode was applied. In the case of single shot LiF crystal irradiation, the energy measurements were provided in each laser shot and for 10 Hz repetition case average laser energy measurements were done. SASE-FEL pulse energy was varied from 4 to 11 μJ in different shots for main laser pulses and from 60 to 165 nJ for 3d harmonic pulses, respectively. The duration of the pulse was estimated at ~(100 – 300) fs [21

21. . Shintake, H. Tanaka, T. Hara, T. Tanaka, K. Togawa, M. Yabashi, Y. Otake, Y. Asano, T. Bizen, T. Fukui, S. Goto, A. Higashiya, T. Hirono, N. Hosoda, T. Inagaki, S. Inoue, M. Ishii, Y. Kim, H. Kimura, M. Kitamura, T. Kobayashi, H. Maesaka, T. Masuda, S. Matsui, T. Matsushita, X. Maréchal, M. Nagasono, H. Ohashi, T. Ohata, T. Ohshima, K. Onoe, K. Shirasawa, T. Takagi, S. Takahashi, M. Takeuchi, K. Tamasaku, R. Tanaka, Y. Tanaka, T. Tanikawa, T. Togashi, S. Wu, A. Yamashita, K. Yanagida, C. Zhang, H. Kitamura, and T. Ishikawa, “A compact free-electron laser for generating coherent radiation in the extreme ultraviolet region,” Nat. Photonics 2(9), 555–559 (2008). [CrossRef]

].

In our experiments we used commercially available LiF crystals with diameter of 20 mm and thickness of 2 mm. Crystals were placed at room temperature in a vacuum chamber at the

distance of 16.3 m from the SASE-FEL beam output (see experimental setup in Fig. 2(a)
Fig. 2 (a) Scheme of the experiments; (b) Typical image and trace of the 61.5 nm SASE-FEL beam intensity distributions obtained on the LiF crystal in one laser shot. Presented image was combined by tiling 3.5 x 3.5 mm luminescence images measured with luminescence microscope with 4X magnification; (c) Magnified (10x) image and trace of the laser beam diffraction on the nickel mesh with period of ~360 μm, placed at the distance of ~26 mm from the LiF crystal detector.
).

After irradiation, the LiF crystals were kept a few days in the dark at room temperature. Then the PL of irradiated crystals was observed with a confocal fluorescence laser microscope (OLYMPUS model FV300). The PL of stable CCs formed by soft X-ray radiation was used to measure the intensity/fluence distribution of SCSS-FEL laser beam at such distance and the typical image and trace are presented in Fig. 2(b). In the case of placing the mesh (Fig. 1(a)) in the downstream of propagated FEL beam at the distance of ~26 mm in front of the LiF crystal detector, patterns were observed, produced due to the coherent diffraction of beam radiation on the mesh (Fig. 2(c)). Diffraction images of the FEL beam were obtained in 1 shot for fundamental wavelength, and in several shots for the FEL harmonics pulses. Also diffraction patterns were obtained by accumulation of a large number of shots (up to 36 000). We did not observe changes in contrast of the diffraction patterns compared with the single shot measurement cases. This shows high stability of SASE-FEL beam parameters (spatial, spectral and coherence properties) from shot to shot. The spectroscopic characterization ofthe CCs PL spectra was done using F-4500 Hitachi Fluorescence Spectral Analyzer. LiF crystals were pumped by different radiation from 200 to 700 nm and photoluminescence spectra were measured in the spectral range of 200 – 700 nm. Typical photoluminescence spectra for blank LiF crystal and LiF crystal irradiated by 61.5 nm SASE-FEL beam are presented in Fig. 3
Fig. 3 (a) Typical plot of PL spectra dependence from pumping excitation wavelengths, obtained for blank and irradiated LiF crystals by 61.5 nm SASE-FEL beams. (b) Spectra of PL for blank and exposed LiF crystals, which were excited by λ1 = 270 and λ2 = 450 nm.
.

3. Experimental results and discussion

3.1 Measurements of LiF crystal PL spectra

As it was shown in Fig. 1, such PL spectra behavior is typical for ultra-short visible laser beam multiphoton interaction with LiF crystals. Moreover, if we compare PL spectra of LiF crystals irradiated by optical laser beams with different pulse durations, and with the ones by SASE-FEL soft X-ray pulses (Fig. 4(b)), we could see that the PL spectrum features in the last case are closer to the spectra features, obtained by irradiation of LiF crystals by the shortest (100 fs) optical laser pulses. It means that our measurements of the PL spectrum of LiF crystals give an indirect confirmation of the fact that the duration of the SASE-FEL beam pulse is of ~100 fs [21

21. . Shintake, H. Tanaka, T. Hara, T. Tanaka, K. Togawa, M. Yabashi, Y. Otake, Y. Asano, T. Bizen, T. Fukui, S. Goto, A. Higashiya, T. Hirono, N. Hosoda, T. Inagaki, S. Inoue, M. Ishii, Y. Kim, H. Kimura, M. Kitamura, T. Kobayashi, H. Maesaka, T. Masuda, S. Matsui, T. Matsushita, X. Maréchal, M. Nagasono, H. Ohashi, T. Ohata, T. Ohshima, K. Onoe, K. Shirasawa, T. Takagi, S. Takahashi, M. Takeuchi, K. Tamasaku, R. Tanaka, Y. Tanaka, T. Tanikawa, T. Togashi, S. Wu, A. Yamashita, K. Yanagida, C. Zhang, H. Kitamura, and T. Ishikawa, “A compact free-electron laser for generating coherent radiation in the extreme ultraviolet region,” Nat. Photonics 2(9), 555–559 (2008). [CrossRef]

]. Thus, our results suggest that redistribution of intensity in the PLspectrum of LiF crystal from the red part of spectra to the green one is associated not with the wavelengths of laser beam irradiation (visible compare with XUV), but with a shortening of the applied laser pulse duration down to pico - or femtosecond range. This result confirms the proposed [3

3. T. Kurobori, T. Kitao, Y. Hirose, K. Kawamura, D. Takamizu, M. Hirano, and H. Hosono, “Laser-active colour centers with functional peridodic structures in LiF fabricated by two interfering femtosecond laser pulses,” Radiat. Meas. 38(4-6), 759–762 (2004). [CrossRef]

] statement, that in the case of LiF crystal irradiation by fs optical pulses, energy deposition into the material can occur before any energy transfer to the layer and in such case, mainly F3+ centers are created.

3.2 Measurements of LiF crystal PL response from the fluence of soft X-ray irradiation

Dependence of peak intensity of 530 nm PL spectra from the soft X-ray fluence was measured by irradiance of LiF crystals from 1 up to 24000 shots of 61.5 nm SASE-FEL pulses. Such variation of FEL shots numbers corresponds to the wide accumulated soft X-ray fluence changes from ~10 μJ/cm2 up to ~260 mJ/cm2. Obtained results are presented in Fig. 5
Fig. 5 Dependence of PL peak intensities (λ = 530 nm) from the accumulated fluence of SASE-FEL beam irradiation of LiF crystal at the wavelengths of 61.5 nm.
showing that at low soft X-ray fluence, intensity of PL spectra increases practically linearly with increasing of the fluence. With additional increasing of soft X-ray fluence higher than ~3 mJ/cm2 this dependence changes and starts to follow a square root law.

To increase the number of measured points and thus to improve the accuracy of our measurements, we proposed to also use another approach. This approach is connected with the fact that the soft X-ray laser beam diffraction [23

23. D. M. Paganin, Coherent X-ray Optics, (Oxford University Press, 2006).

] on the mesh could be modeled nowadays with a very high accuracy. It means that we could compare experimental intensities of the SASE-FEL beam after diffraction on the mesh with modeled one. Suppose that, in the case of a linear response of the detector, the measured intensity distribution in diffraction patterns should coincide with modeled one, we consider that any discrepancy between normalized experimental and modeled intensities of diffraction peaks is mainly caused by nonlinearity of detector response. In our experimental case the discrepancy between experimental and modeled intensities of diffraction patterns increased with an increasing of SXRL fluence. This fact proves the nonlinearity of detector response. In order to define detector response function we should transform experimental diffraction intensities to fit modeled one.

For modeling diffracted by mesh the SASE-FEL beam the parabolic wave equation
2ikuz+2ux2+2uy2=0,E=u(x,y,z)eikz,k=2πλ
(1)
was applied. Using Eq. (1) for 2D case the diffracted field was found in the form
u(x,z)=k2πizu0(ξ)exp[ik(xξ)22z]dξ
(2)
on the assumption
u0(ξ)={0,|ξ|<d/21,|ξ|>d/2
(3)
where u0(ξ) is the initial distribution of the field, z is the distance along the laser beam propagation and d is the diameter of wire in the mesh.

Simulated intensity distribution in diffraction pattern on the plane of detector, traced perpendicular to the mesh wire, is shown in Figs. 6(a)
Fig. 6 The soft X-ray coherent diffraction patterns, measured at ~26 mm distance from the Ni mesh. The square mesh with 36.5 μm size of wire and period of 360 μm was irradiated by SASE-FEL beam with wavelength of 61.5 nm by one (a) and by 30 laser shots (b). Good reproducibility of SASE-FEL beam optical properties from shot to shot is clearly seen from the high contrast of diffraction patterns in the last case. (c) The PL spectra peak intensities (λ = 530 nm) dependences on the fluence of SASE-FEL beam irradiation of LiF crystal at the wavelengths of 61.5 nm were obtained by diffraction and by direct measurements.
and 6(b) in red. For comparison in the same plots experimentally measured intensity distribution Iexp(x) is shown in black. From thefigures it follows that periods of diffraction patterns are in good coincidence for both plots, but the lowest and peak intensities are not in agreement. To reach the appropriate agreement in intensities we compared experimental intensities Iexp(x) (in black) with calculated Im(x) ones (in red) in 4 points (see Figs. 6(a) and 6(b)): at I(x1) = Imax; I(x2) = 1; I(x3) = Imin and in the center of geometrical shadow I(x = 0) = I0. By means of linear interpolation the dependence of Iexp(Im) was obtained and inverse function was used for correction of experimental diffraction of intensities. Results of carried out procedure are presented in Fig. 6(a), 6(b) in blue line with open circles. A very good coincidence of corrected experimental and modeled diffraction patterns is demonstrated, both for their period and intensities.

We applied the above mentioned procedure of LiF crystal response determination for wide range of fluence, when 1, 10, 30, 300 and 600 shots of SASE-FEL laser pulses diffracted on the mesh and accumulated by the LiF crystal detector. The results of the reconstruction of LiF crystal PL response to the soft X-ray beam fluence obtained using diffraction method procedure are presented in Fig. 6(c) and are compared with the results measured by using the direct method of measurements of the curve described above. Solid agreement between the two methods of measurements is clearly seen.

4. Conclusion

Using a high-intensity, monochromatic, femtosecond soft X-ray irradiation of LiF crystals by SASE-FEL beams allowed producing high - performance optical characterization of colorization processes of such crystals, which is a fundamental metrological aspect for their application as the sensitive soft X-ray imaging detectors with submicron spatial resolution. It is necessary to stress the fact that our measurements of the PL spectrum of LiF crystals give indirect evidence that the duration of the SASE-FEL beam pulse is of ~100 fs. Another very important result found was the absence of quenching phenomena even at relatively high soft X-ray fluence, which is of particular relevance not only for the use of LiF as an imaging detector based on optical simulated luminescence of active CCs, but also for the fundamental aspects of other applications. This is also very important as it will allow us to define accurate local values of the propagated SASE - FEL soft X-ray beam intensity, to measure the quality of its profile along beam propagation, and to find exact values of the real local fluence at a target surface after focusing of the FEL beam. Characterization of LiF – based detector for harder X-ray emission and improvements of its performance are currently under further development.

Acknowledgments

This work is supported by the “X-ray Free Electron Laser utilization research project” of the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan and partly by the Presidium of the Russian Academy of Sciences programs 2 and 22.

References and links

1.

J. H. Schulman and W. D. Compton, Color Centers in Solids, (Oxford, 1962).

2.

W. L. McLaughlin, A. C. Lucas, B. M. Kapsar, and A. Miller, “Electron and gamma-ray dosimetry using radiation induced color centers in LiF,” Radiat. Phys. Chem. 14, 467–480 (1979).

3.

T. Kurobori, T. Kitao, Y. Hirose, K. Kawamura, D. Takamizu, M. Hirano, and H. Hosono, “Laser-active colour centers with functional peridodic structures in LiF fabricated by two interfering femtosecond laser pulses,” Radiat. Meas. 38(4-6), 759–762 (2004). [CrossRef]

4.

T. Kurobori, T. Yamakage, Y. Hirose, K. Kawamura, M. Hirano, and H. Hosono, “Application of wide-band-gap materials for optoelectronic functional devices fabricated by a pair of interfering femtosecond laser pulses,” Jpn. J. Appl. Phys. 44(2), 910–913 (2005). [CrossRef]

5.

F. Bonfigli, A. Faenov, F. Flora, T. Marolo, R. M. Montereali, E. Nichelatti, T. Pikuz, L. Reale, and G. Baldacchini, “Point defects in lithium fluoride films for micro-radiography, X-Ray microscopy and photonic applications,” Phys. Status Solidi 202(2), 250–255 (2005) (a). [CrossRef]

6.

G. Baldacchini, F. Bonfigli, F. Flora, R. M. Montereali, D. Murra, E. Nichelatti, A. Ya. Faenov, and T. A. Pikuz, “High-contrast photoluminiscent patterns in lithium fluoride crystals produced by soft X-rays from a laser-plasma source,” Appl. Phys. Lett. 80(25), 4810–4812 (2002). [CrossRef]

7.

G. Baldacchini, F. Bonfigli, A. Faenov, F. Flora, R. M. Montereali, A. Pace, T. Pikuz, and L. Reale, “Lithium fluoride as a novel X-ray image detector for biological μ-world capture,” J. Nanosci. Nanotechnol. 3(6), 483–486 (2003). [CrossRef] [PubMed]

8.

G. Tomassetti, A. Ritucci, A. Reale, L. Palladino, L. Reale, L. Arrizza, G. Baldacchini, F. Bonfigli, F. Flora, L. Mezi, R. M. Montereali, S. V. Kukhlevsky, A. Faenov, T. Pikuz, and J. Kaiser, “High-resolution Imaging of a soft X-ray laser beam by color centers excitation in lithium fluoride crystals,” Europhys. Lett. 63(5), 681–686 (2003). [CrossRef]

9.

G. Baldacchini, S. Bollanti, F. Bonfigli, F. Flora, P. Di Lazzaro, A. Lai, T. Marolo, R. M. Montereali, D. Murra, A. Faenov, T. Pikuz, E. Nichelatti, G. Tomassetti, A. Reale, L. Reale, A. Ritucci, T. Limongi, L. Palladino, M. Francucci, S. Martellucci, and G. Petrocelli, “Soft x-ray submicron imaging detector based on point defects in LiF,” Rev. Sci. Instrum. 76(11), 113104 (2005). [CrossRef]

10.

F. Calegari, G. Valentini, C. Vozzi, E. Benedetti, J. Cabanillas-Gonzalez, A. Faenov, S. Gasilov, T. Pikuz, L. Poletto, G. Sansone, P. Villoresi, M. Nisoli, S. De Silvestri, and S. Stagira, “Elemental sensitivity in soft x-ray imaging with a laser-plasma source and a color center detector,” Opt. Lett. 32(17), 2593–2595 (2007). [CrossRef] [PubMed]

11.

F. Bonfigli, A. Faenov, F. Flora, M. Francucci, P. Gaudio, A. Lai, S. Martellucci, R. M. Montereali, T. Pikuz, L. Reale, M. Richetta, M. A. Vincenti, and G. Baldacchini, “High-resolution water window X-ray imaging of in vivo cells and their products using LiF crystal detectors,” Microsc. Res. Tech. 71(1), 35–41 (2008). [CrossRef] [PubMed]

12.

Y. Fukuda, A. Ya. Faenov, T. Pikuz, M. Kando, H. Kotaki, I. Daito, J. Ma, L. M. Chen, T. Homma, K. Kawase, T. Kameshima, T. Kawachi, H. Daido, T. Kimura, T. Tajima, Y. Kato, and S. V. Bulanov, “Soft X-ray source for nanostructure imaging using femtosecond – laser – irradiated clusters,” Appl. Phys. Lett. 92(12), 121110 (2008). [CrossRef]

13.

A. Ya. Faenov, Y. Kato, M. Tanaka, T. A. Pikuz, M. Kishimoto, M. Ishino, M. Nishikino, Y. Fukuda, S. V. Bulanov, and T. Kawachi, “Submicrometer-resolution in situ imaging of the focus pattern of a soft x-ray laser by color center formation in LiF crystal,” Opt. Lett. 34(7), 941–943 (2009). [CrossRef] [PubMed]

14.

T. A. Pikuz, A. Ya. Faenov, S. V. Gasilov, I. Yu. Skobelev, Y. Fukuda, M. Kando, H. Kotaki, T. Homma, K. Kawase, Y. Hayashi, T. Kawachi, H. Daido, Y. Kato, and S. V. Bulanov, “Propagation-based phase-contrast enhancement of nanostructure images using a debris-free femtosecond-laser-driven cluster-based plasma soft x-ray source and an LiF crystal detector,” Appl. Opt. 48(32), 6271–6276 (2009). [CrossRef] [PubMed]

15.

S. V. Gasilov, A. Ya. Faenov, T. A. Pikuz, Y. Fukuda, M. Kando, T. Kawachi, I. Yu. Skobelev, H. Daido, Y. Kato, and S. V. Bulanov, “Wide-field-of-view phase-contrast imaging of nanostructures with a comparatively large polychromatic soft x-ray plasma source,” Opt. Lett. 34(21), 3268–3270 (2009). [CrossRef] [PubMed]

16.

S. Almaviva, F. Bonfigli, I. Franzini, A. Lai, R. M. Montereali, D. Pelliccia, A. Cedola, and S. Lagomarsino, “Hard x-ray contact microscopy with 250 nm spatial resolution using a LiF film detector and a tabletop microsource,” Appl. Phys. Lett. 89(5), 054102 (2006). [CrossRef]

17.

M. Matsubayashi, A. Faenov, T. Pikuz, Y. Fukuda, and Y. Kato, “Neutron imaging of micron-size structures by color center formation in LiF crystals,” Nucl. Instrum. Meth. A 622(3), 637–641 (2010). [CrossRef]

18.

T. Kurobori, K. Kawamura, M. Hirano, and H. Hosono, “Simultaneous fabrication of laser-active colour centers and permanent microgratings in lithium fluoride by a single femtosecond pulse,” J. Phys- Condens Mat. 15, 399–405 (2003).

19.

L. C. Courrol, R. E. Samad, L. Gomez, I. M. Ranieri, S. L. Baldochi, A. Zanardi de Freitas, and N. D. Vieira Jr., “Color center production by femtosecond pulse laser irradiation in LiF crystals,” Opt. Express 12(2), 288–293 (2004). [CrossRef] [PubMed]

20.

F. Bonfigli, F. Flora, I. Franzini, E. Nichelatti, and R. M. Montereali, “Optical characterization of a soft X-ray imaging detector based on photoluminiscent point defects in lithium fluoride thin layer,” J. Lumin. 129(12), 1964–1967 (2009). [CrossRef]

21.

. Shintake, H. Tanaka, T. Hara, T. Tanaka, K. Togawa, M. Yabashi, Y. Otake, Y. Asano, T. Bizen, T. Fukui, S. Goto, A. Higashiya, T. Hirono, N. Hosoda, T. Inagaki, S. Inoue, M. Ishii, Y. Kim, H. Kimura, M. Kitamura, T. Kobayashi, H. Maesaka, T. Masuda, S. Matsui, T. Matsushita, X. Maréchal, M. Nagasono, H. Ohashi, T. Ohata, T. Ohshima, K. Onoe, K. Shirasawa, T. Takagi, S. Takahashi, M. Takeuchi, K. Tamasaku, R. Tanaka, Y. Tanaka, T. Tanikawa, T. Togashi, S. Wu, A. Yamashita, K. Yanagida, C. Zhang, H. Kitamura, and T. Ishikawa, “A compact free-electron laser for generating coherent radiation in the extreme ultraviolet region,” Nat. Photonics 2(9), 555–559 (2008). [CrossRef]

22.

M. Kato, N. Saito, T. Tanaka, Y. Morishita, H. Kimura, H. Ohashi, M. Nagasono, M. Yabashi, K. Tono, T. Togashi, A. Higashiya, and T. Ishikawa, “Pulse energy of the extreme - ultraviolet free - electron laser at SPring-8 determined using a cryogenic radiometer,” Nucl. Instrum. Meth. A 612(1), 209–211 (2009). [CrossRef]

23.

D. M. Paganin, Coherent X-ray Optics, (Oxford University Press, 2006).

OCIS Codes
(110.7440) Imaging systems : X-ray imaging
(120.0120) Instrumentation, measurement, and metrology : Instrumentation, measurement, and metrology
(140.7240) Lasers and laser optics : UV, EUV, and X-ray lasers

ToC Category:
Imaging Systems

History
Original Manuscript: October 31, 2011
Revised Manuscript: December 16, 2011
Manuscript Accepted: January 4, 2012
Published: January 30, 2012

Citation
Tatiana Pikuz, Anatoly Faenov, Yuji Fukuda, Masaki Kando, Paul Bolton, Alexander Mitrofanov, Alexander Vinogradov, Mitsuru Nagasono, Haruhiko Ohashi, Makina Yabashi, Kensuke Tono, Yashinori Senba, Tadashi Togashi, and Tetsuya Ishikawa, "Optical features of a LiF crystal soft x-ray imaging detector irradiated by free electron laser pulses," Opt. Express 20, 3424-3433 (2012)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-20-4-3424


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. J. H. Schulman and W. D. Compton, Color Centers in Solids, (Oxford, 1962).
  2. W. L. McLaughlin, A. C. Lucas, B. M. Kapsar, and A. Miller, “Electron and gamma-ray dosimetry using radiation induced color centers in LiF,” Radiat. Phys. Chem.14, 467–480 (1979).
  3. T. Kurobori, T. Kitao, Y. Hirose, K. Kawamura, D. Takamizu, M. Hirano, and H. Hosono, “Laser-active colour centers with functional peridodic structures in LiF fabricated by two interfering femtosecond laser pulses,” Radiat. Meas.38(4-6), 759–762 (2004). [CrossRef]
  4. T. Kurobori, T. Yamakage, Y. Hirose, K. Kawamura, M. Hirano, and H. Hosono, “Application of wide-band-gap materials for optoelectronic functional devices fabricated by a pair of interfering femtosecond laser pulses,” Jpn. J. Appl. Phys.44(2), 910–913 (2005). [CrossRef]
  5. F. Bonfigli, A. Faenov, F. Flora, T. Marolo, R. M. Montereali, E. Nichelatti, T. Pikuz, L. Reale, and G. Baldacchini, “Point defects in lithium fluoride films for micro-radiography, X-Ray microscopy and photonic applications,” Phys. Status Solidi202(2), 250–255 (2005) (a). [CrossRef]
  6. G. Baldacchini, F. Bonfigli, F. Flora, R. M. Montereali, D. Murra, E. Nichelatti, A. Ya. Faenov, and T. A. Pikuz, “High-contrast photoluminiscent patterns in lithium fluoride crystals produced by soft X-rays from a laser-plasma source,” Appl. Phys. Lett.80(25), 4810–4812 (2002). [CrossRef]
  7. G. Baldacchini, F. Bonfigli, A. Faenov, F. Flora, R. M. Montereali, A. Pace, T. Pikuz, and L. Reale, “Lithium fluoride as a novel X-ray image detector for biological μ-world capture,” J. Nanosci. Nanotechnol.3(6), 483–486 (2003). [CrossRef] [PubMed]
  8. G. Tomassetti, A. Ritucci, A. Reale, L. Palladino, L. Reale, L. Arrizza, G. Baldacchini, F. Bonfigli, F. Flora, L. Mezi, R. M. Montereali, S. V. Kukhlevsky, A. Faenov, T. Pikuz, and J. Kaiser, “High-resolution Imaging of a soft X-ray laser beam by color centers excitation in lithium fluoride crystals,” Europhys. Lett.63(5), 681–686 (2003). [CrossRef]
  9. G. Baldacchini, S. Bollanti, F. Bonfigli, F. Flora, P. Di Lazzaro, A. Lai, T. Marolo, R. M. Montereali, D. Murra, A. Faenov, T. Pikuz, E. Nichelatti, G. Tomassetti, A. Reale, L. Reale, A. Ritucci, T. Limongi, L. Palladino, M. Francucci, S. Martellucci, and G. Petrocelli, “Soft x-ray submicron imaging detector based on point defects in LiF,” Rev. Sci. Instrum.76(11), 113104 (2005). [CrossRef]
  10. F. Calegari, G. Valentini, C. Vozzi, E. Benedetti, J. Cabanillas-Gonzalez, A. Faenov, S. Gasilov, T. Pikuz, L. Poletto, G. Sansone, P. Villoresi, M. Nisoli, S. De Silvestri, and S. Stagira, “Elemental sensitivity in soft x-ray imaging with a laser-plasma source and a color center detector,” Opt. Lett.32(17), 2593–2595 (2007). [CrossRef] [PubMed]
  11. F. Bonfigli, A. Faenov, F. Flora, M. Francucci, P. Gaudio, A. Lai, S. Martellucci, R. M. Montereali, T. Pikuz, L. Reale, M. Richetta, M. A. Vincenti, and G. Baldacchini, “High-resolution water window X-ray imaging of in vivo cells and their products using LiF crystal detectors,” Microsc. Res. Tech.71(1), 35–41 (2008). [CrossRef] [PubMed]
  12. Y. Fukuda, A. Ya. Faenov, T. Pikuz, M. Kando, H. Kotaki, I. Daito, J. Ma, L. M. Chen, T. Homma, K. Kawase, T. Kameshima, T. Kawachi, H. Daido, T. Kimura, T. Tajima, Y. Kato, and S. V. Bulanov, “Soft X-ray source for nanostructure imaging using femtosecond – laser – irradiated clusters,” Appl. Phys. Lett.92(12), 121110 (2008). [CrossRef]
  13. A. Ya. Faenov, Y. Kato, M. Tanaka, T. A. Pikuz, M. Kishimoto, M. Ishino, M. Nishikino, Y. Fukuda, S. V. Bulanov, and T. Kawachi, “Submicrometer-resolution in situ imaging of the focus pattern of a soft x-ray laser by color center formation in LiF crystal,” Opt. Lett.34(7), 941–943 (2009). [CrossRef] [PubMed]
  14. T. A. Pikuz, A. Ya. Faenov, S. V. Gasilov, I. Yu. Skobelev, Y. Fukuda, M. Kando, H. Kotaki, T. Homma, K. Kawase, Y. Hayashi, T. Kawachi, H. Daido, Y. Kato, and S. V. Bulanov, “Propagation-based phase-contrast enhancement of nanostructure images using a debris-free femtosecond-laser-driven cluster-based plasma soft x-ray source and an LiF crystal detector,” Appl. Opt.48(32), 6271–6276 (2009). [CrossRef] [PubMed]
  15. S. V. Gasilov, A. Ya. Faenov, T. A. Pikuz, Y. Fukuda, M. Kando, T. Kawachi, I. Yu. Skobelev, H. Daido, Y. Kato, and S. V. Bulanov, “Wide-field-of-view phase-contrast imaging of nanostructures with a comparatively large polychromatic soft x-ray plasma source,” Opt. Lett.34(21), 3268–3270 (2009). [CrossRef] [PubMed]
  16. S. Almaviva, F. Bonfigli, I. Franzini, A. Lai, R. M. Montereali, D. Pelliccia, A. Cedola, and S. Lagomarsino, “Hard x-ray contact microscopy with 250 nm spatial resolution using a LiF film detector and a tabletop microsource,” Appl. Phys. Lett.89(5), 054102 (2006). [CrossRef]
  17. M. Matsubayashi, A. Faenov, T. Pikuz, Y. Fukuda, and Y. Kato, “Neutron imaging of micron-size structures by color center formation in LiF crystals,” Nucl. Instrum. Meth. A622(3), 637–641 (2010). [CrossRef]
  18. T. Kurobori, K. Kawamura, M. Hirano, and H. Hosono, “Simultaneous fabrication of laser-active colour centers and permanent microgratings in lithium fluoride by a single femtosecond pulse,” J. Phys- Condens Mat.15, 399–405 (2003).
  19. L. C. Courrol, R. E. Samad, L. Gomez, I. M. Ranieri, S. L. Baldochi, A. Zanardi de Freitas, and N. D. Vieira., “Color center production by femtosecond pulse laser irradiation in LiF crystals,” Opt. Express12(2), 288–293 (2004). [CrossRef] [PubMed]
  20. F. Bonfigli, F. Flora, I. Franzini, E. Nichelatti, and R. M. Montereali, “Optical characterization of a soft X-ray imaging detector based on photoluminiscent point defects in lithium fluoride thin layer,” J. Lumin.129(12), 1964–1967 (2009). [CrossRef]
  21. . Shintake, H. Tanaka, T. Hara, T. Tanaka, K. Togawa, M. Yabashi, Y. Otake, Y. Asano, T. Bizen, T. Fukui, S. Goto, A. Higashiya, T. Hirono, N. Hosoda, T. Inagaki, S. Inoue, M. Ishii, Y. Kim, H. Kimura, M. Kitamura, T. Kobayashi, H. Maesaka, T. Masuda, S. Matsui, T. Matsushita, X. Maréchal, M. Nagasono, H. Ohashi, T. Ohata, T. Ohshima, K. Onoe, K. Shirasawa, T. Takagi, S. Takahashi, M. Takeuchi, K. Tamasaku, R. Tanaka, Y. Tanaka, T. Tanikawa, T. Togashi, S. Wu, A. Yamashita, K. Yanagida, C. Zhang, H. Kitamura, and T. Ishikawa, “A compact free-electron laser for generating coherent radiation in the extreme ultraviolet region,” Nat. Photonics2(9), 555–559 (2008). [CrossRef]
  22. M. Kato, N. Saito, T. Tanaka, Y. Morishita, H. Kimura, H. Ohashi, M. Nagasono, M. Yabashi, K. Tono, T. Togashi, A. Higashiya, and T. Ishikawa, “Pulse energy of the extreme - ultraviolet free - electron laser at SPring-8 determined using a cryogenic radiometer,” Nucl. Instrum. Meth. A612(1), 209–211 (2009). [CrossRef]
  23. D. M. Paganin, Coherent X-ray Optics, (Oxford University Press, 2006).

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.


« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited