A sensitive and high dynamic range cw laser power meter.
We report the design of a cost effective, highly sensitive cw laser power meter with a large dynamic range based on a photodiode. The power meter consists of a photodiode, a current to voltage converter circuit, an offset balancing circuit, a microcontroller, an analog to digital converter, reed relays, and an alphanumeric liquid crystal display. The power meter can record absolute laser power levels as low as 1 pW. The dynamic range measured with a cw laser at a wavelength of 532 nm is 8x10(10). The high sensitivity and large dynamic range are achieved by the implementation of an analog background balancing circuit and autoranging.
Krishnan
S
S
Laser Physics Applications Division, Raja Ramanna Centre for Advanced Technology, Indore 452013, India. skrish@rrcat.gov.in
Bindra
K S
KS
Oak
S M
SM