A V Fedenev

Ultraviolet And Infrared Lasers With High Efficiency

repetition rate and a pulse width of 10 ns. The input pulse propagates through a poLarizer P,, a Faraday rotator and a polarizer P,. The pulse then passes through the slab amplifier eight times and is extracted by using polarization rotation. The Nd: YAG slab (4 mm X 8 mm X 35 mm) is pumped from both sides by four quasiCW (200 k s ) 300W LD arrays at 50 Hz repetition rate. The LD arrays were fabricated by Hamamatsu Photonics K.K. The slab is cut for normal incidence to eliminate polarization dependent loss and the input faces (four in total) are AR coated at 1064 nm. The thermal birefringence in the slab is compensated by means of a 90 degree quartz rotator. Figure 2 shows energy extraction efficiency of the amplifier plotted as a function of the initial small signal gain. From Fig. 2, it is seen that the extraction efficiency increased after thermal birefringence compensation especially at higher small signal gain values. A maximum extraction efficiency of up to 58% was obtained at a small signal gain of 2.01. The stored energy was estimated to be 19 mJ while the output energy of the 8-pass amplifier was 13 mJ at the maximum energy of the LD arrays. The successful operation of this system demonstrates that it is applicable and scalable to the design of higher power laser systems with high efficiency and high beam quality. *Central Research Laboratory, Hamamatsu Photonics K.K. 5000, Hirakuchi, Hamakita, Shizuoka 434, JAPAN

Temperature dependence of Teflon transmission factor under TEA-CO 2 laser irradiation

The experimental results of the studies on process of radiation interaction of the pulsed CO2 - laser with polytetrafluoroethylene (PTFE) are presented. A dependence of PTFE transmission factor at λ = 10.6 μm versus temperature in the range -90 - 300°C has been obtained.

Teflon sputtering under pulsed CO/sub 2/-laser irradiation

Teflon plate is irradiated by pulsed CO/sub 2/ laser. A crater with even edges without traces of melt or blackening was formed after irradiation of the teflon plate surface by focussed pulsed radiation of CO/sub 2/-laser with p.r.r. of /spl sim/1 Hz. Increasing of PTFE surface temperature resulted in increase of efficiency of teflon mass removed from the crater. Increasing of teflon target surface temperature or laser pulse duration results in greater amount of PTFE mass sputtered per shot, increase in particle sizes and appearance of fiber-like formations. Teflon sputtering velocities and powder particles distribution by size at pulse duration of 100 ns and 15 /spl mu/s and specific power of 10/sup 8/ and 10/sup 6/ W/cm/sup 2/, correspondingly, have been define.

Laser test of adhesion of thin metal films on glass substrate

In this paper, it is suggested to use pulsed laser radiation to define adhesion of thin metallic films to the substrate and surface defects detection. The preliminary experimental data on Xe- and XeCl-lasers interaction with thin films of metals deposited on glass using technology of vacuum-arc evaporation are presented in the paper. Threshold laser radiation power densities necessary for film detachment from the substrate are determined. Thus, a possibility of testing of thin film adhesion by focused pulsed laser irradiation with known power distribution over cross-section has been demonstrated.