Method and means for stabilizing the amplitude and repetition frequency of a repetitively q-switched laser

Claim 3

The method of claim 1, in which light above said given amplitude level is removed by generating an electrical signal of wave form following that of each output pulse; providing a constant reference signal of value corresponding to said given amplitude level; combining the signals to provide a control signal; passing the output pulses through a first polarizing means; controlling the direction of polarization of said polarizing means by said control signal such that light above said given amplitude only is blocked from passing through said first polarizing means so that the output pulses from said first polarizing means all have uniform amplitudes, the selecting of a narrow time channel within the pulse width of each pulse being accomplished by passing the output pulses of uniform amplitudes from said first polarizing means to a second polarizing means; and changing the direction of polarization of said second polarizing means by said timing signal to a new direction for given time periods at precise poInts in time corresponding to the time positions of the pulses during which said pulses are passed through said second polarizing means, each of the given time periods defining the narrow time channel within the pulse width.

Claim 4

A means for stabilizing the amplitude and repetition frequency of a repetitively Q-switched laser comprising: a. first means positioned to receive output pulses from said laser to limit the amplitude of said pulses to a given uniform amplitude; b. second means positioned to receive the uniform amplitude pulses from said first means and optically gate said pulses to pass only an intermediate portion of the pulse between its leading and trailing edges as defined by a gating signal; and c. means connected to said second means for providing said gating signal in time synchronism with the Q-switching of said laser.

Claim 5

A means for stabilizing the amplitude and repetition frequency of a repetitively Q-switched laser comprising: a. first means positioned to receive output pulses from said laser to limit the amplitude of said pulses to a given uniform amplitude; b. second means positioned to receive the uniform amplitude pulses from said first means and optically gate said pulses to pass only an intermediate portion of the pulse between its leading and trailing edges as defined by a gating signal; and c. means connected to said second means for providing said gating signal in time synchronism with the Q-switching of said laser.

Claim 6

A repetitively Q-switched laser system for providing output pulses of uniform amplitude, pulse width and repetition frequency, comprising, in combination: a. a laser medium; b. pumping means for said medium; c. end mirrors defining an optical cavity for said medium; d. Q-switching means in said optical cavity for enabling generation of laser pulses at a given pulse repetition frequency defined by the frequency of operation of said Q-switching means; e. means for monitoring each output pulse to provide electrical signal pulses of wave form following the amplitude contour of said output pulses; f. means for generating a reference signal of given amplitude; g. differential amplifier means receiving said electrical signal pulses and reference signal to provide output control signals; h. a first polarizing means connected to receive said control signals; i. delay means receiving the output light pulses and passing said pulses to said first polarizing means after a given time delay sufficient to assure that said output pulses arrive at said first polarizing means at the same time as said control signals, said control signals controlling the direction of polarization of said first polarizing means such that light above a given amplitude determined by said reference signal is blocked from passing through said first polarizing means so that the output pulses of said first polarizing means are all of uniform amplitudes; j. means for generating an electrical gating signal defining a narrow time channel of constant time period less than the pulse width of the output light pulses in response to generation of each light pulse in said laser system; and k. a second polarizing means connected to receive said gating signal, said uniform amplitude pulses from said first polarizing means being passed to said second polarizing means, said gating signal changing the direction of polarization of said second polarizing means during said constant time period only to pass the light pulses through said second polarizing means whereby the output pulses from said second polarizing means are uniform in amplitude, pulse width and repetition frequency.

Claim 7

A repetitively Q-switched laser system for providing output pulses of uniform amplitude, pulse width and repetition frequency, comprising, in combination: a. a laser medium; b. pumping means for said medium; c. end mirrors defining an optical cavity for said medium; d. Q-switching means in said optical cavity for enabling generation of laser pulses at a given pulse repetition frequency defined by the frequency of operation of said Q-switching means; e. means for monitoring each output pulse to provide electrical signal pulses of wave form following the amplitude contour of said output pulses; f. means for generating a reference signal of given amplitude; g. differential amplifier means receiving said electrical signal pulses and reference signal to provide output control signals; h. a first polarizing means connected to receive said control signals; i. delay means receiving the output light pulses and passing said pulses to said first polarizing means after a given time delay sufficient to assure that said output pulses arrive at said first polarizing means at the same time as said control signals, said control signals controlling the direction of polarization of said first polarizing means such that light above a given amplitude determined by said reference signal is blocked from passing through said first polarizing means so that the output pulses of said first polarizing means are all of uniform amplitudes; j. means for generating an electrical gating signal defining a narrow time channel of constant time period less than the pulse width of the output light pulses in response to generation of each light pulse in said laser system; and k. a second polarizing means connected to receive said gating signal, said uniform amplitude pulses from said first polarizing means being passed to said second polarizing means, said gating signal changing the direction of polarization of said second polarizing means during said constant time period only to pass the light pulses through said second polarizing means whereby the output pulses from said second polarizing means are uniform in amplitude, pulse width and repetition frequency.

Claim 8

A laser system according to claim 4, in which said means for generating said gating signal is connected to said monitoring means so that generation of said gating signals is responsive to said electrical signal pulses.

Claim 9

A laser system according to claim 4, in which said means for generating said gating signal is connected to said Q-switching means so that generation of said gating signals is responsive to Q-switching of said laser.