Masakatsu Sugii

Simple long-pulse XeCl laser with narrow-line output

Long-pulsed operation of a capacitive transfer driven XeCl laser using inductors has been demonstrated with no degradation of the laser performance. Spectral narrowing to a 0.003 A bandwidth with an output energy of 4 mJ was also achieved using a grating and etalon combination.

High locking efficiency XeCl ring amplifier injection locked by backward stimulated Brillouin scattering

Performance of a XeCl ring amplifier injection locked by backward stimulated Brillouin scattering is described. High locking efficiency of ∼100% and a high‐quality beam have been successfully obtained by using a Brillouin mirror.

MINIATURE TEA-CO2 LASER WITH SURFACE-WIRE-CORONA PREIONIZATION

This paper describes an experimental study of a miniature, UV‐preionized TEA‐CO2 laser with a new type of surface‐wire‐corona preionizer. We have developed a surface‐wire‐corona preionizer consisting of segmented columnar SrTiO3 dielectric and a fine wire strained on the dielectric surface, we believe for the first time. By applying this preionizer to the TEA‐CO2 laser, efficient laser operation at an overall efficiency of 8.9% with an output energy of 114 mJ has been achieved from a small discharge volume of 5.8 cm3 with active length of 14.5 cm. This efficiency is comparable to the maximum one obtained with miniature TEA‐CO2 laser reported up to now.

Single-state high-beam-quality XeCl laser with a phase-conjugate Brillouin mirror

A single-stage high-beam-quality XeCl laser, consisting of an oscillator and a double-pass amplifier with a phase-conjugate Brillouin mirror with no optical coupling between the oscillator and the amplifier, is discussed. Maximum output energy of 20 mJ with a pulse duration of 13 ns full width at half maximum has been obtained with a 0.0015-AA (469-MHz) linewidth, 1.2*diffraction-limited beam divergence from a circular 8-mm diameter beam. >

High-efficiency XeCl discharge laser with high-brightness SrTiO/sub 3/ corona preionizer

An XeCl discharge laser with a high-brightness corona preionizer using a segmented columnar SrTiO/sub 3/ dielectric is discussed. A high overall efficiency of 2.35% with a laser output energy of 350 mJ was obtained using a SrTiO/sub 3/ doorknob capacitor cut by a diamond cutter as the dielectric. These characteristics are almost the same value as that obtained with an UV-spark-preionized XeCl laser using the same laser tube.<<ETX>>

Compact, semi‐sealed‐off, high‐repetition‐rate XeCl laser with a surface‐wire‐corona preionization

This paper describes the design and operating characteristics of a reasonably compact, semi‐sealed‐off, high‐efficiency XeCl laser operating at prfs <170 Hz by a stable discharge system using a new type of surface‐wire‐corona preionizer. An efficient laser operation at a slope efficiency of 1.6% with an average power of 4.1 W (150 Hz) has been achieved from a discharge volume of 52 cc with an active length of 26 cm. With a small amount of H2 as additive, ≳2×106 shots have been achieved on a single gas fill and an estimated half‐power lifetime of 3×107 shots made.

High-power, tunable, high-repetition rate TEA-/sup 13/C/sup 18/O/sub 2/ laser

The authors report the power enhancement of a high-repetition-rate TEA-/sup 13/C/sup 18/O/sub 2/ laser by substitution of rare /sup 15/N/sub 2/ isotope instead of /sup 14/N/sub 2/ and its tunable single-mode operation. Efficient, high-power operation with a maximum average power of 25 W (100 Hz) at a slope efficiency of 5.6%, which is improved by a factor of 2 by substitution of /sup 15/N/sub 2/ instead of /sup 14/N/sub 2/, has been successfully achieved from a discharge volume of 57.5 cm/sup 3/ with an active length of 26 cm. In addition, high-power, tunable, single-mode operation has been achieved with a three-mirror cavity consisting of two mirrors and a Littrow grating. >

Midinfrared atmospheric transmittance measurements by using the second and third harmonics of tunable TEA-CO2 lasers

The middle-infrared wavelength region around 3-5 m corresponds to the best optical laser band for high atmospheric transmittance and eye-safety. Middle-infrared lasers are used in laser range finders, laser radars, and so on. There are only a few reports on the atmospheric laser transmittance of these middle-infrared optical bands. This paper describes, we believe for the first time, middle-infrared atmospheric transmittance characteristics as measured by the second and third harmonics of tunable TEA-CO2 lasers. The experimental results showed that the laser transmittance at 3.4 - 3.6 m correlated well with the results calculated by the HITRAN-PC code, assuming a middle-latitude, summer condition. The measured transmittance at 4.6 - 4.8 ,um exhibited a fine-structure, probably due to the absorption of atmospheric molecules such as NO2 and H20.

Compact, semi‐sealed‐off, high‐repetition‐rate transversely excited atmospheric‐pressure CO2 laser with a surface‐wire‐corona preionization

This article describes the design and operating characteristics of a reasonably compact, semi‐sealed‐off, high‐efficiency transversely excited atmospheric‐pressure CO2 laser operating at prfs <150 Hz by a stable discharge system using a new type of surface‐wire‐corona preionizer. An efficient laser operation at a slope efficiency of 10.2% with a maximum average power of 42 W (100 Hz) has been achieved from a discharge volume of 57.5 cc with an active length of 26 cm. With CO and H2 as additive, ≳2.1×106 shots has been achieved on a single gas fill and an estimated half‐power lifetime of 2×107 shots made.

High Speed Operation of a Multidither Adaptive Optical System and Real-Time Compensation of Dynamic Phase Fluctuation

A high speed operation of a multidither adaptive optical system (MAOS) with a ninesegmented adaptive mirror and real-time compensation of dynamic phase fluctuation has beendemonstrated. Experimental results are as follows: (1) A high speed operation of MAOS withan indicial response time of 55 ms has been achieved with a new type of wavefront controlmethod by using the saturation characteristics of a photo-detector (2) Dynamic CO2-laserwavefront distortion with a spot dancing of 47 μrad (rms), induced by two gas burners, hasbeen compensated in real time by the high-speed operation of the control system. The laserbeam was then converged within a nearly diffraction limit, improving the laser peak intensity by afactor of 2.8 with a Strehl Ratio of 0.8. A frequency spectrum measurement of the detectorsignal also confirmed that the turbulence spectrum component was automatically suppressed.