We present experimental intracavity absorption measurements carried out in a commercial Ar+-ion laser with a modified resonator. The samples were aqueous solutions of Rhodamine 6G. The smallest detectable concentration was 1 × 10−13 mol/L for λ = 488 nm. This is equivalent to an internal absorbance of 3.5 × 10−9. Similar measurements were performed with λ = 514.5 nm, but time- and space-periodic intensity fluctuations, particularly at lower light levels, reduced the sensitivity of the absorption detection.
© 1988 Optical Society of America
Original Manuscript: September 29, 1987
Manuscript Accepted: March 25, 1988
Published: June 1, 1988
E. Kleist and H. Bettermann, "Intracavity absorption measurements from liquid samples in an Ar+-ion laser," Opt. Lett. 13, 449-451 (1988)