How to Improve Output Power Stability of Green DPSS Laser Systems
In various high tech scientific research works, continuous and pulsed green lasers are able to fulfill majority of applications. However, in some of special working fields, such as laser light fluorescence, lighting absorption, light scattering method, and precise measurements, green DPSS laser systems are always in serious requirement of high output power stability. As a result, it is extremely important for laser tech engineers to pay high attention to development and research of higher quality lasers.
There are a lot of factors which might cause unstable output power emission of green DPSS laser. For instance, beam stability might be affected by a lot of factors such as unstable resonator mechanical structure, operating temperature change, thermal lens effect, pump source power fluctuation, absorption of green light laser crystal, mode hopping etc. In those of extremely strict requirement of laser beam stability work fields, users should try many methods thus ensuring high performance of 532nm green DPSS laser.
In current high tech work fields, laser tech engineer have developed polarization control, longitudinal mode control, external cavity frequency doubling, photoelectric feedback of modulator etc. According to exact requirement of laser application in different work field, green DPSS laser system has just specially designed thus always getting high power stability.
1. Direct control laser diode driving of photoelectric feedback method to improve beam stability of green laser output power. According to detected output power change single of green laser, with feedback control of pumping laser diode working electric driving, making active control of laser diode output power, thus realize control of output power of green DPSS lasers, thus making great improvement of beam stability of green lasers.
2. Continuous or pulsed green laser beam emission from green DPSS laser passes through filter system. Filter system filters unabsorbed laser light by laser crystal, including 808nm and 1064nm pump light. When passing through beam splitter for laser light selecting, part of 532nm green laser light is reflected onto optic detector to inspect light intensity change.
Electrical single getting from optic detector is input into feedback controller to make amplified or processing. The feedback controller produced control signal is sent into laser driver, making perfect control of LD driving current, thereby changing the LD pumping power of laser crystal, making compensation of fluctuation of green laser output power, thus achieving high stability of 532nm green DPSS laser system.
Under free running condition, the output power of green DPSS laser has relatively large change in operation. This large variation performance 532nm green DPSS laser system is not able to fulfill the requirement of beam stability of different users. According to active measures, the beam stability always gets extremely high improvement. Within 4 hours continuous beam projection, beam stability of green laser system gets superior performance of as high as ±0.5%. According to advanced photoelectric feedback method of making direct control of LD driving current, green laser beam stability can seriously be improved, thus allowing easy and convenient operation in all work fields.
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