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Frequently asked questions

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Adaptive optics.

Question: How does deformable mirror effect on laser mode behavior?
Answer: No effects if mirror is outside a resonator.
Mode composition of radiation from a laser with deformable mirror inside is not worse, than at usage of usual optics. Moreover, an adaptive deformable mirror enables to change operatively or dynamically laser mode composition.

Q: Is it possible to increase power of radiation of the laser by substitution of a usual mirror with deformable one?
A: Generally is not. The power of radiation can increase with usage of a deformable mirror, if not a quite optimal laser resonator was utilized.

Q: What are characteristic deformation frequencies of your mirrors and possible frequencies of control?
A: The first resonance frequency of mirrors AT22 and AT24 is about 7,5 kHz, AT26 - about 3,2 kHz. The possible speed of response, as a rule, in a greater degree is restricted by the speed of the control algorithm and possibilities of the block of control, for which the deformable mirror is an electric capacity load.

Q: Does a deformable mirror effect on noise performances of laser radiation?
A: It depends; but the mirror enables to control this laser characteristic also.

Q: Is it possible to provide a mirror with a cover withstanding against impulse radiation powered, say, of several GW at a pulse duration some fs?
A: Yes, it is possible.

Q: What is life expectancy of the mirrors?
A: The mirror withstands more than 109 cycles of a complete deformation, however in substantial conditions the life expectancy of deformable mirrors is restricted to resistance of a coverage and does not differ from usual (monolithic) mirrors.


Q: What is a hysteresis?
A: The hysteresis is rather widespread physical phenomenon, when a value of a response on effect depends not only on an instantaneous amplitude of the effect, but also on values of the effect in the past.
For a deformable mirror it means that the dependence of a movement on applied voltage has nonlinear and ambiguous character.
The magnitude of a hysteresis can be characterized by a ratio f0/fa. A typical value of this ratio is 0.2. The influence of a hysteresis can be reduced, applying other piezomaterials, placing a position feedback, etc.

Q: Is it possible to produce a deformable mirror similar as AT26, but with diameter 85 mm? 90 mm? 150 mm?
A: It is possible. Now our technological base allows producing mirrors with dimensional size up to 300 mm. We plan to manufacture such size mirror in 2002.

Q: Is it possible to produce a mirror similar as AT26 with other layout of electrodes?
A: It is possible. The technique of segmentation available now allows to make any layout with the minimum size of a segment about 1 mm and interval between electrodes of 0.2-0.4 mm (limited with electrical breakdown strength). The tolerance of execution of these sizes is less than 0.05 mm.



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