Laser power-energy meter

Claim 1

A meter for measuring over a wide wavelength bandwidth and wide pulse length the pulse energy and CW power of light from a source such as a laser to provide safety monitoring comprising photo-diode means acting as a current generator having an output directly proportional to the optical power incident upon it, a multiplicity of filters, each of said filters capable of passing a preselected wavelength in accordance with the wavelength of the light being measured, first means to select one of said multiplicity of filters in accordance with the wavelength of the light to be measured, said first selecting means being disposed between said photo-diode means and said light source, aperture means disposed between the selected filter and said photo-diode means permitting the filtered light to be incident upon said photo-diode means, said aperture means having a predetermined diameter in the region of the average diameter of the human pupil, a multiplicity of loads for said photo-diode means, each of said loads being a capacitor or a resistor in accordance with the pulse energy or CW power, respectively, of said light being measured, second means to select one of said loads in accordance with the pulse energy or CW power being measured, means to short the selected load to ground at a predetermined rate and period, means to amplify the output signal from said photo-diode means, said amplifying means having an input and output and including a gain controlling feedback network, said feedback network being comprised of a multiplicity of potentiometers connected in parallel from the output of said amplifying means to ground, third selecting means to select one of the arms of said multiplicity of potentiometer for connection to said input of said first amplifying means to provide the proper gain for each wavelength selected to compensate for the spectral response of said photo-diode means and the characteristics of the selected filters, said first, second, and third selecting means being interconnected and controlled in unison to provide the proper filter, load, and gain, respectively, in accordance with the wavelength of the light being measured, fourth means to select from the output of said amplifying means the highest value of pulse or CW power, and means to measure the energy in the selected pulse or the magnitude of CW power.