Widely tunable fourth harmonic generation of a Ti:sapphire laser based on RBBF crystal

Fourth harmonic generation of a tunable Ti:sapphire laser with a repetition rate of 80?MHz and pulse duration ??150 fs has been realized in a single pass with an RbBe₂BO₃F₂ crystal for the first time. A high average power was obtained which was tunable throughout a wide range from 180 to 232.5?nm. The output power over the whole range exceeded 2?mW, the highest being 43.3?mW at 202.5?nm. Moreover, deep-ultraviolet output with powers above 75?mW was obtained at 193.5 and 200?nm under a stronger focusing condition. This is the first attempt at the generation of tunable deep-ultraviolet light without using a KBBF crystal, which is very difficult to grow due to its strong layering tendency, and our attempt may provide new opportunities for the development of all-solid-state deep-ultraviolet coherent light sources.     

High-resolution LIF measurements on hyperfine structure and isotope shifts in various states of Lu I using the second and third harmonic of a cw Ti:sapphire laser

With the second and third harmonic of a tunable single-mode cw Ti:S laser, generated inside external enhancement cavities, high-resolution LIF measurements on several states of Lu I in various parts of the electromagnetic spectrum are performed. From these measurements, hyperfine structure A and B constants for both ¹⁷⁵Lu and ¹⁷⁶Lu as well as isotope shifts have been determined for all levels observed in the single-step excitation process. From the measured A constants, the magnetic hyperfine structure anomaly has been derived for various states. Received 14 January 2002 Published online 19 July 2002     

Efficiency of fluorescence excitation in chlorophyll <Emphasis Type="Italic">a</Emphasis> by the second and third harmonics of emission from an Nd:YAG laser

We have studied the efficiency of fluorescence excitation in chlorophyll a by the second harmonic (532 nm) and the third harmonic (355 nm) of an Nd:YAG laser for sea water samples with phytoplankton taken during different algal blooms and for extracts of higher plants diluted with sea water. We have shown that when using the second harmonic, the efficiency of fluorescence excitation in chlorophyll a is more than twice as high as for excitation by the third harmonic. We discuss the advisability of using the second or third harmonics of the emission from an Nd:YAG laser when studying the biooptical parameters of sea water. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 2, pp. 224–227, March–April, 2008.     

The application of an unstable resonator to a high-pressure CW CO2 laser

Unstable resonators provide high quality beams of high output power needed for material processing. We have developed a CO₂ laser of over 5 kW for material processing with an unstable resonator of positive confocal configuration under high-pressure, sealed condition. High quality beams with high extraction efficiency of the power were obtained and deep pentration was attained in welding tests.