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APPLICATIONS-CENTERED RESEARCH IN OPTICS

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September


Refractive-diffractive dispersion compensation for optical vortex beams with ultrashort pulse durations

  • Manfred Musigmann, Juergen Jahns, Martin Bock, and Ruediger Grunwald
  • received 06/20/2014; accepted 09/22/2014; posted 09/25/2014; Doc. ID 214361
  • [full text: PDF (1905) KB)]
  • Abstract: Wave fields which are mathematically described by higher order Bessel functions carry an orbital angular momentum and thus represent particular types of optical vortex beams with helical wavefronts. For the generation of such vortex beams, one may use, for instance, diffractive spiral axicons. Diffraction, however, leads invariably to strong dispersion, which is detrimental for ultrashort pulses since it leads to severe pulse broadening. This pulse broadening can be minimized or completely reduced (at least, in a specific plane of propagation), if the pulses propagate additionally through a medium with normal refractive dispersion. The refractive-diffractive generation of ultrashort vortex pulses was demonstrated earlier for a pulse duration of approximately 8 fs [M. Bock, J. Jahns, and R. Grunwald, Opt. Lett. 37, 3804-3806 (2012)]. Here, we present an analytical description of the generation and propagation of these vortex beams and of the refractive-diffractive compensation of the dispersion.

Keywords (OCIS):

  • (140.7090) Lasers and laser optics : Ultrafast lasers
  • (320.5540) Ultrafast optics : Pulse shaping
  • (050.4865) Diffraction and gratings : Optical vortices

Gold crescent nanodisk array for nanoantenna-enhanced sensing in subwavelength areas

  • Zhen Zhang, Bingpu Zhou, Yingzhou Huang, Zhongwei Liao, Shunbo Li, Shuxia Wang, and Weijia Wen
  • received 07/10/2014; accepted 09/21/2014; posted 09/25/2014; Doc. ID 216448
  • [full text: PDF (1563) KB)]
  • Abstract: Benefiting from the antenna effect and localized surface plasmon resonance (LSPR), metal nanoparticle with designed morphology has the amazing ability to confine light energy into the required extremely small volume, whose refractive index largely affect the optical properties of the whole metal nanoparticle. In this work, the optical spectra and near-field distribution of gold nanocrescent array were investigated both experimentally and theoretically. To find out the LSPR wavelength and the enhancement with different morphologies of sharp tips, the spectra of gold nanocrescent array with different waist widths (d) were measured firstly, which are then confirmed and analyzed through finite-difference time-domain method and hybridization theory. At last, the LSPR of this array with 100nm diameter dielectric nanodisk were studied for sensing in subwavelength area. Our results figured out this gold nanocrescent array could be a suitable local senor to sensing the variation of local medium in a subwavelength area for its giant nanoantenna-enhanced EM field at the two tips.

Keywords (OCIS):

  • (240.6680) Optics at surfaces : Surface plasmons
  • (280.4788) Remote sensing and sensors : Optical sensing and sensors
  • (250.5403) Optoelectronics : Plasmonics

Injection seeded single-frequency pulsed Nd:YAG laser resonated by an intracavity phase modulator

  • Junxuan Zhang, Xiaolei Zhu, Huaguo Zang, Xiuhua Ma, Suyong Yin, Shiguang Li, and Weibiao Chen
  • received 08/06/2014; accepted 09/21/2014; posted 09/23/2014; Doc. ID 220508
  • [full text: PDF (1956) KB)]
  • Abstract: A reliable single frequency Q-switched Nd:YAG laser is developed by using an lithium niobate crystal as the intracavity phase modulator. Successfully injection seeding is performed by adopting an electro-optic crystal in an effectively simplified cavity arrangement. The laser is capable of producing 4.8 mJ pulse-energy at 400 Hz repetition rate with nearly Fourier-transform- limited spectral linewidth. The pulse duration is around 25 ns, and the beam quality factor M2 is less than 1.3.

Keywords (OCIS):

  • (140.3540) Lasers and laser optics : Lasers, Q-switched
  • (140.3570) Lasers and laser optics : Lasers, single-mode
  • (140.3580) Lasers and laser optics : Lasers, solid-state

Accurate frequency noise measurement of free running lasers

  • Max Schiemangk, Stefan Spießberger, Andreas Wicht, Gotz Erbert, Guenther Traenkle, and Achim Peters
  • received 06/19/2014; accepted 09/20/2014; posted 09/23/2014; Doc. ID 212865
  • [full text: PDF (362) KB)]
  • Abstract: We present a simple method to accurately measure the frequency noise power spectrum of lasers. It relies on creating the beat note between two lasers, capturing the corresponding signal in the time domain, and appropriately post-processing the data to derive the frequency noise power spectrum. In contrast to methods already established it does not require stabilization of the laser to an optical reference, i.e. a second laser, to an optical cavity, or to an atomic transition. It further omits a frequency discriminator and hence avoids bandwidth-limitation and non-linearity effects common to high resolution frequency discriminators.

Keywords (OCIS):

  • (120.0120) Instrumentation, measurement, and metrology : Instrumentation, measurement, and metrology
  • (120.5050) Instrumentation, measurement, and metrology : Phase measurement
  • (140.3460) Lasers and laser optics : Lasers
  • (140.5960) Lasers and laser optics : Semiconductor lasers

Mechanisms and kinetics of short pulse laser-induced destruction of silver containing nano-particles in multicomponent silicate photo-thermo-refractive glass

  • Julien Lumeau and Leonid Glebov
  • received 07/01/2014; accepted 09/20/2014; posted 09/23/2014; Doc. ID 214506
  • [full text: PDF (576) KB)]
  • Abstract: Photo-thermo-refractive (PTR) glass is a photosensitive multi-component glass which is commercially used for the recording of volume holographic elements and finds many applications in advanced laser systems. Refractive index decrement in this glass is observed after UV exposure followed by thermal development. This procedure also causes the appearance of Ag containing particles that can be then optically bleached by using the second harmonic of a Nd:YAG laser. Despite the broad usage of this method, its mechanisms are still unclear. In this paper, a systematic study of the short pulse laser-induced destruction of Ag containing particles kinetics versus incident energy per pulse and dosage is presented. We show that no beaching of Ag containing particles occurs for energy density in laser pulses below 0.1 J/cm2 while above 1 J/cm2, the efficiency of bleaching saturates. Efficiency of bleaching depends on the type of particles to be bleached (Ag, AgBr…). Using a simple model of short pulse laser interaction with nano-particles embedded in glass, the temperature of the Ag containing particles reached during the laser interaction is shown to be large enough to produce complete dissipation of these particles which is expected to be the main mechanisms of short pulse laser-induced destruction of Ag containing particles.

Keywords (OCIS):

  • (300.1030) Spectroscopy : Absorption
  • (140.3538) Lasers and laser optics : Lasers, pulsed
  • (160.5335) Materials : Photosensitive materials

(LITH2014) Transport of Intensity phase imaging in the presence of curl effects induced by strongly absorbing photomasks

  • Aamod Shanker, Lei Tian, Martin Sczyrba, Brid Connolly, Andrew Neureuther, and Laura Waller
  • received 07/09/2014; accepted 09/19/2014; posted 09/19/2014; Doc. ID 216606
  • [full text: PDF (1805) KB)]
  • Abstract: Traditional Transport of Intensity Equation (TIE) solvers recover phase from through-focus intensity images under the assumption that the underlying in-plane power flow is curl-free. Motivated by the study of polarization-dependent electromagnetic phase edges in lithography masks, we describe a practical situation in which this assumption breaks down. Strong absorption gradients interacting with phase edges contribute a curl to the in-plane Poynting vector, causing severe artifacts in the recovered phase. We derive how curl effects are coupled into intensity measurements and propose an iterative algorithm which both corrects the artifacts and recovers missing curl components.

Keywords (OCIS):

  • (100.5070) Image processing : Phase retrieval
  • (110.3960) Imaging systems : Microlithography
  • (080.4865) Geometric optics : Optical vortices

Procedure for measuring solar and visible properties simultaneously of glazing with complex internal or external structures

  • A. G. and G. Smith
  • received 07/11/2014; accepted 09/19/2014; posted 09/19/2014; Doc. ID 216830
  • [full text: PDF (1377) KB)]
  • Abstract: Accurate solar and visual transmittance of materials in which surfaces or internal structures are complex are often not easily amenable to standard procedures with laboratory based spectrophotometers and integrating spheres. Localized “hot spots” of intensity are common in such materials, so data on small samples is unreliable. A novel device and simple protocols have been developed and undergone validation testing. Simultaneous solar and visible transmittance and reflectance data has been acquired for skylight components and multilayer polycarbonate roof panels. The pyranometer and lux sensor set-ups also directly yield “light coolness” in Lumens/Watt. Sample areas must be large and though mainly in sheet form some testing has been done on curved panels. The instrument, its operation, and the simple calculations used are described. Results on a sub-set of diffuse and partially diffuse materials with no hot-spots have been cross-checked using 150 mm integrating spheres with spectrophotometer and the Air Mass 1.5 spectrum. Indications are that results are as good or better than with such spheres for transmittance but reflectance techniques need refinement for some sample types.

Keywords (OCIS):

  • (120.4800) Instrumentation, measurement, and metrology : Optical standards and testing
  • (160.5470) Materials : Polymers
  • (290.5880) Scattering : Scattering, rough surfaces
  • (350.6050) Other areas of optics : Solar energy
  • (150.2945) Machine vision : Illumination design

Vibrationally excited hydroxyl tagging velocimetry

  • Nathan Grady and Robert Pitz
  • received 07/16/2014; accepted 09/19/2014; posted 09/19/2014; Doc. ID 217115
  • [full text: PDF (1582) KB)]
  • Abstract: A new molecular-based velocity method is developed for high temperature flame gases based on the Hydroxyl Tagging Velocimetry (HTV) technique. In Vibrationally-Excited HTV (VE-HTV), two photons from a KrF laser (248 nm) dissociate H2O into a tag line of vibrationally excited OH (v=1). The excited state OH tag is selectively detected in a background of naturally occurring ground state OH (v=0). In atmospheric pressure laboratory burners, the OH (v=1) tag persists for 5-10 μs allowing single-shot velocity measurements along a 2 cm line under lean, stoichiometric, and rich flame conditions with temperatures reaching 2300 K. Mean velocity measurements are demonstrated in a lean (φ = 0.78) premixed H2/air turbulent flame (Re = 26,550) laboratory flame. The VE-HTV method is best suited to measure high-speed velocities in hot combustion environments in the presence of background OH.

Keywords (OCIS):

  • (120.0120) Instrumentation, measurement, and metrology : Instrumentation, measurement, and metrology
  • (120.1740) Instrumentation, measurement, and metrology : Combustion diagnostics
  • (120.7250) Instrumentation, measurement, and metrology : Velocimetry

Diffuse Optics using a Dual Window Fast-Gated Counter

  • Laura Di Sieno, Alberto Dalla Mora, Gianluca Boso, Alberto Tosi, Antonio Pifferi, Rinaldo Cubeddu, and Davide Contini
  • received 07/16/2014; accepted 09/18/2014; posted 09/24/2014; Doc. ID 216996
  • [full text: PDF (1035) KB)]
  • Abstract: In this paper we demonstrate the advantages of a fast-gated counter in achieving high count rate and reducing costs of timing equipment in a time-resolved diffuse optical spectroscopy setup. We experimentally prove the equivalence between the fast-gated counter we developed and a traditional time-correlated single-photon counting setup in terms of depth sensitivity and signal-to-noise ratio. Additionally, we show the suitability of this device for bilayer analysis and to estimate the absorption coefficient of homogeneous diffusing media. Finally, we present a proof-of-principle arterial occlusion measurement on a healthy volunteer to validate the proposed approach in a real application. Fast-gated counters can dramatically reduce both costs and complexity in time-resolved multichannel systems, while achieving high count rate, thus offering a great advantage in applications like brain and muscle functional imaging.

Keywords (OCIS):

  • (030.5260) Coherence and statistical optics : Photon counting
  • (170.3660) Medical optics and biotechnology : Light propagation in tissues
  • (170.6920) Medical optics and biotechnology : Time-resolved imaging
  • (290.7050) Scattering : Turbid media
  • (040.1345) Detectors : Avalanche photodiodes (APDs)

One-Shot Depth Acquisition with Random Binary Pattern

  • Qin Li, Fu Li, Guangming Shi, Shan Gao, Ruodai Li, Lili Yang, and Xuemei Xie
  • received 06/19/2014; accepted 09/17/2014; posted 09/17/2014; Doc. ID 214340
  • [full text: PDF (1332) KB)]
  • Abstract: In this paper, we propose a new spatial encoding method which integrates the random binary pattern and the improved phase difference matching method to acquire a dense and precise depth map. The adopted binary pattern can simplify the pattern projecting devices compared with the colorful pattern. The density of speckles in the pattern is periodical and the positions of them are random. Based on thes two properties, we propose an improved phase-difference corresponding method which is divided into two steps: the coarse matching step to estimate the approximate coordinates of pixels in the pattern via analyzing the phase values of the image, and the fine matching step to compensate errors of the coarse matching results and to achieve sub-pixel accuracy. This matching method does not require an extra optimization method with a high computation complexity. In the experiment, we show the effectiveness of the proposed method. We also evaluate this method in actual experiments. The results show the advantages of this method compared with the TOF camera and Kinect.

Keywords (OCIS):

  • (110.6880) Imaging systems : Three-dimensional image acquisition
  • (150.5670) Machine vision : Range finding
  • (150.6910) Machine vision : Three-dimensional sensing

X-ray optics of gold nanoparticles

  • Renat Letfullin, Colin Rice, and Thomas George
  • received 07/01/2014; accepted 09/17/2014; posted 09/18/2014; Doc. ID 215102
  • [full text: PDF (489) KB)]
  • Abstract: Gold nanoparticles have been investigated as contrast agents for traditional X-ray medical procedures, utilizing the strong absorption characteristics of the nanoparticles to enhance the contrast of the detected X-ray image. Here we use the Kramers-Kronig relation for complex atomic scattering factors to find the real and imaginary parts of the index of refraction for the medium composed of single-element materials or compounds in the X-ray range of the spectrum. These complex index of refraction values are then plugged into a Lorenz-Mie theory to calculate the absorption efficiency of various size gold nanoparticles for photon energies in the 1-100 keV range. Since the output from most medical diagnostic X-ray devices follow a wide and filtered spectrum of photon energies, we introduce and compute the effective intensity-absorption-efficiency values for gold nanoparticles of radii varying from 5 to 50 nm, where we use the tungsten anode spectral model interpolating polynomials (TASMIP) model to integrate over all spectral energies generated by typical tungsten anode X-ray tubes with kilovolt potentials ranging from 50 to 150 kVp.

Keywords (OCIS):

  • (160.4760) Materials : Optical properties
  • (170.5180) Medical optics and biotechnology : Photodynamic therapy
  • (340.0340) X-ray optics : X-ray optics
  • (350.4990) Other areas of optics : Particles
  • (160.4236) Materials : Nanomaterials

Inverse Analysis of Light Scattered at a Small Angle for Characterization of a Transparent Dielectric Fiber

  • Grzegorz Swirniak, Grzegorz Glomb, and Janusz Mroczka
  • received 07/08/2014; accepted 09/17/2014; posted 09/18/2014; Doc. ID 216550
  • [full text: PDF (1232) KB)]
  • Abstract: The objective of this paper is to discuss the possibility of non-invasive, optical characterization of a transparent (glass) fiber by means of low-coherent light scattering. It will be shown, that by adjusting the coherence properties of incident light, it is possible to select these specific orders of scattering which are related to diffraction. Discussion will be devoted to both the direct scattering and the inverse problem, where an inference about diameter of a multilayered and transparent fiber is accomplished.

Keywords (OCIS):

  • (060.2270) Fiber optics and optical communications : Fiber characterization
  • (290.3200) Scattering : Inverse scattering
  • (290.5850) Scattering : Scattering, particles
  • (290.2558) Scattering : Forward scattering

Common-path and compact wavefront diagnosis system based on cross grating lateral shearing interferometer

  • Tong Ling, Yongying Yang, Xiumei Yue, Dong Liu, and Yifang Ma
  • received 08/07/2014; accepted 09/17/2014; posted 09/18/2014; Doc. ID 220528
  • [full text: PDF (1118) KB)]
  • Abstract: A common-path and compact wavefront diagnosis system for both continuous and transient wavefronts measurement is proposed based on cross grating lateral shearing interferometer (CGLSI). Derived from the basic CGLSI configuration, this system employs an aplanatic lens to convert the wavefront under test into a convergent beam, which makes it possible for CGLSI to test the wavefront of collimated beams. A geometrical optics model for grating pitch determination and a Fresnel diffraction model for order selection mask design are presented. Then a detailed analysis about the influence of the grating pitch, the distance from the cross grating to the order selection mask and the numerical aperture of the aplanatic lens on the system error is made, and a calibration method is proposed to eliminate the system error. In addition, the differential Zernike polynomials fitting method is introduced for wavefront retrieval. Before our experiment, we have designed several grating pitches and their corresponding order selection mask parameters. In the final comparative experiment with ZYGO interferometer, the wavefront diagnosis system exhibits both high precision and repeatability.

Keywords (OCIS):

  • (050.1950) Diffraction and gratings : Diffraction gratings
  • (120.0120) Instrumentation, measurement, and metrology : Instrumentation, measurement, and metrology
  • (120.3180) Instrumentation, measurement, and metrology : Interferometry
  • (120.5050) Instrumentation, measurement, and metrology : Phase measurement

Research on object-plane constraints and hologram expansion in phase retrieval algorithms for CW terahertz inline digital holography reconstruction

  • Jiaqi Hu, Qi Li, and Shanshan Cui
  • received 07/22/2014; accepted 09/16/2014; posted 09/17/2014; Doc. ID 217516
  • [full text: PDF (1503) KB)]
  • Abstract: In terahertz inline digital holography, the zero-order diffraction light and conjugate image cause reconstructed image misty. In this paper, three phase retrieval algorithms with different object-plane constrain are applied to conduct reconstruction under the same near-field diffraction propagation conditions and image-plane constraint. The impacts of different object-plane constraints on terahertz inline digital holographic reconstruction are studied. The results show that it is not suitable for phase retrieval algorithm to impose restriction on the phase when the object is a little complicated in the terahertz inline digital holography. In addition, the effects of zero-padding expansion, boundary replication expansion and apodization operation on reconstructed images are studied. The results indicate that the conjugate image can be eliminated and a better reconstructed image can be obtained by adopting appropriate phase retrieval algorithm after the normalized hologram extending to the minimum area which meets the applicable range of angular spectrum reconstruction algorithm by means of boundary replication.

Keywords (OCIS):

  • (090.1995) Holography : Digital holography
  • (110.6795) Imaging systems : Terahertz imaging

Luminescence enhancement in nanocomposite consisting of polyvinyl alcohol incorporated gold nanoparticles and nile blue 690 perchlorate

  • Ketevan Chubinidze, Besarion Partsvania, Tamaz Sulaberidze, Aleksandre Khuskivadze, Elene Davitashvili, and Nana Koshoridze
  • received 04/21/2014; accepted 09/15/2014; posted 09/19/2014; Doc. ID 210132
  • [full text: PDF (662) KB)]
  • Abstract: We demonstrate that the emission of visible light from the polymer matrix doped with luminescence dye and gold nanoparticles (GNPs) can be enhanced with the use of surface plasmon coupling. GNPs can enhance the luminescence of nearby luminescent dye because the interactions between the dipole moments of the dye and the surface plasmon field of the GNPs. By matching the plasmon frequency of GNPs to the frequency of pumping light source we have observed a luminescent enhancement of the nanopomposite consisting of GNPs coupled luminescent dye nile blue 690 perchlorate. Besides this enhancement depends on the distance between GNP and luminescent dye.

Keywords (OCIS):

  • (160.2540) Materials : Fluorescent and luminescent materials
  • (160.5470) Materials : Polymers
  • (160.4236) Materials : Nanomaterials

Arrange & Average algorithm for the retrieval of aerosol parameters from multiwavelength HSRL/Raman lidar data

  • Eduard Chemyakin, Detlef Muller, Sharon Burton, Alexei Kolgotin, Chris Hostetler, and Richard Ferrare
  • received 07/18/2014; accepted 09/15/2014; posted 09/16/2014; Doc. ID 213875
  • [full text: PDF (913) KB)]
  • Abstract: We present the results of a feasibility study in which a new, simple, automated and unsupervised algorithm, which we call the Arrange & Average algorithm, is used to infer microphysical parameters (complex refractive index, effective radius, total number, surface-area and volume concentrations) of atmospheric aerosol particles. The algorithm uses backscatter coefficients at 355, 532, and 1064 nm, and extinction coefficients at 355 and 532 nm as input information. Testing of the algorithm is based on synthetic optical data that are computed from prescribed monomodal particle size distributions and complex refractive indices which describe spherical, fine mode pollution particles. We tested the performance of the algorithm for the “3 backscatter (fiβ) + 2 extinction (α)” configuration of a multiwavelength aerosol HSRL or Raman lidar. We investigated the degree to which the microphysical results retrieved by this algorithm depend on the number of input backscatter and extinction coefficients. For example, we tested “3β + 1α”, “2β + 1α”, and “3βfi” lidar configurations. This Arrange & Average algorithm can be used in two ways. First, it can be applied for quick data processing of experimental data acquired with lidar. Fast automated retrievals of microphysical particle properties are needed in view of the enormous amount of data that can be acquired by the NASA Langley Research Center’s airborne “3β + 2α” high-spectral-resolution lidar (HSRL-2). It would prove useful for the growing number of ground-based multiwavelength lidar networks, and it would provide an option for analyzing the vast amount of optical data acquired with a future spaceborne multiwavelength lidar. The second potential application is to improve the microphysical particle characterization with our existing inversion algorithm that uses Tikhonov’s inversion with regularization. This advanced algorithm has recently undergone development to allow automated and unsupervised processing; the Arrange & Average can be used as a pre-classifier to further improve its speed and precision. First tests of the performance of Arrange & Average algorithm are encouraging. We used a set of 48 different monomodal particle size distributions, 4 real parts and 15 imaginary parts of the complex refractive index. All in all we tested 2880 different optical data sets for 0%, 10%, and 20% Gaussian measurement noise (one-standard deviation). In the case of the “3β + 2α” configuration with 10% measurement noise, we retrieve the particle effective radius to within 27% for 1964 (68.2%) of the test optical data sets. Number concentration is obtained to 76%, the surface-area concentration to 16%, and the volume concentration to 30% precision. The “3fiβ” configuration performs significantly poorer. The performance of the “3fiβ + 1α” and “2β + 1α” configurations is intermediate between the “3β + 2α” and the “3βfi”.

Keywords (OCIS):

  • (000.3860) General : Mathematical methods in physics
  • (010.1100) Atmospheric and oceanic optics : Aerosol detection
  • (010.1110) Atmospheric and oceanic optics : Aerosols
  • (010.3640) Atmospheric and oceanic optics : Lidar

Multi-band localized spoof plasmons in closed textured cavities

  • Bingzheng Xu, Zhuo Li, Changqing Gu, Pingping Ning, Liangliang Liu, Zhenyi Niu, and Yongjiu Zhao
  • received 07/14/2014; accepted 09/15/2014; posted 09/16/2014; Doc. ID 216983
  • [full text: PDF (867) KB)]
  • Abstract: In this work, we explore the existence of multi-band localized spoof plasmons (LSPs) in closed textured cavities with multiple groove depths. It is interesting to note that the spoof LSPs in each band resemble those generated by the textured two-dimensional (2D) cavities of the same periodicity with the corresponding single groove depth. And the field distributions and confinement characteristics of the plasmon-like modes in such a corrugated cavity are different with the conventional cavity. Hence, this multiple resonance band structures can find potential applications in the microwave and terahertz frequencies.

Keywords (OCIS):

  • (140.4780) Lasers and laser optics : Optical resonators
  • (240.6680) Optics at surfaces : Surface plasmons
  • (070.5753) Fourier optics and signal processing : Resonators

Scalable pumping approach for extracting the maximum TEM00 solar laser power

  • Dawei Liang, Joana Almeida, and Cláudia Vistas
  • received 06/12/2014; accepted 09/14/2014; posted 09/15/2014; Doc. ID 214013
  • [full text: PDF (1106) KB)]
  • Abstract: A scalable TEM00 solar laser pumping approach is composed of four pairs of first-stage Fresnel lens-folding mirror collectors, four fused silica secondary concentrators with light guides of rectangular cross-section for radiation homogenization, four hollow two-dimensional compound parabolic concentrators (2D-CPC) for further concentration of uniform radiations from the light guides to a 3 mm diameter, 76 mm length Nd:YAG rod within four V-shaped pumping cavities. An asymmetric resonator ensures an efficient large-mode matching between pump light and oscillating laser light, 59.1W TEM00 laser power is calculated by ZEMAX© and LASCAD© numerical analysis, revealing 20 times improvement in brightness figure of merit.

Keywords (OCIS):

  • (140.0140) Lasers and laser optics : Lasers and laser optics
  • (140.3410) Lasers and laser optics : Laser resonators
  • (140.3530) Lasers and laser optics : Lasers, neodymium
  • (140.5560) Lasers and laser optics : Pumping
  • (350.6050) Other areas of optics : Solar energy
  • (350.6830) Other areas of optics : Thermal lensing

Application of Sub-Doppler DAVLL to the laser frequency stabilization in atomic cesium

  • Dian-Qiang Su, Teng-Fei Meng, Zhong-Hua Ji, Jin-Peng Yuan, Yan-Ting Zhao, Lian-Tuan Xiao, and Suo-Tang Jia
  • received 07/09/2014; accepted 09/14/2014; posted 09/15/2014; Doc. ID 216461
  • [full text: PDF (864) KB)]
  • Abstract: We achieve laser frequency stabilization by a simple technique based on Sub-Doppler dichroic atomic vapor laser lock (DAVLL) in atomic cesium. The technique that combines saturated absorption spectroscopy (SAS) and Zeeman splitting of hyperfine structure allows us to obtain a modulation-free dispersion-like error signal for frequency stabilization. For the error signal, the dependence of peak-to-peak amplitude and the slope at zero-crossing point on magnetic field is studied by simulation and experiment. Base on the result, we obtain an available Sub-Doppler DAVLL error signal with a high sensitivity to the frequency drift by selecting an appropriate strength of magnetic field. Ultimately, the fluctuation of locked laser frequency is confined below 0.5 MHz in a long term exhibiting an efficient suppression of frequency noise.

Keywords (OCIS):

  • (140.0140) Lasers and laser optics : Lasers and laser optics
  • (300.6260) Spectroscopy : Spectroscopy, diode lasers
  • (140.3425) Lasers and laser optics : Laser stabilization

Calculation of the finesse of an ideal Fabry-Pérot resonator

  • Martin Suter and Peter Dietiker
  • received 08/06/2014; accepted 09/14/2014; posted 09/15/2014; Doc. ID 220398
  • [full text: PDF (474) KB)]
  • Abstract: A new derivation of an exact finesse F for the description of an optical resonator is reported. The finesse is derived using the superposition principle of plane waves in an ideal Fabry-Pérot resonator in combination with the standard definition of the quality factor Q which relates the energy loss of a resonator cycle to the energy stored in the resonator. The derived exact expression of the finesse is compared to equations found in the literature and show that they are based on approximations. The exact finesse is then used to convert an infinite series of Lorentz-functions into the well-known Airy-equation in the case of neglected absorption. The derived expression provides a framework for the discussion of the finesse in terms of decay times, free spectral ranges and resonator line widths. The provided expression for the finesse is valid for any value of the intensity relfectivity and gives insight into the underlying physical principles of resonators.

Keywords (OCIS):

  • (230.5750) Optical devices : Resonators
  • (260.5740) Physical optics : Resonance
  • (300.6360) Spectroscopy : Spectroscopy, laser

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