Determination of the frequency of laser radiation

Claim 1

A method for selectively stabilizing a multi-frequency laser at one or more preselected frequencies wherein said laser emits a plurality of beams each having a corresponding frequency, wavelength and power curve, the method comprising selecting at least two of said plurality of beams, adjusting the optical length of the resonant cavity of said laser to a length substantially equal to the value L where L is defined by the equation:2nL k1 lambda 1 k2 lambda 2 . . . ki lambda i where k1, k2 . . . ki are whole numbers >0; lambda 1, lambda 2 . . . lambda i are the preselected wavelengths; n is the index of refraction of the resonant cavity; so that a central dip occurs at a point between two peaks of equal amplitude in the most energetic of said power curves associated with said selected beams, utilizing said point as a reference point, monitoring the output of said laser to detect any shift of said dip from said reference point, and further adjusting said optical length so that said dip is maintained at said point.

Claim 2

A method for selectively stabilizing a multi-frequency laser at one or more preselected frequencies wherein said laser emits a plurality of beams each having a corresponding frequency, wavelength and power curve, the method comprising selecting at least two of said plurality of beams, adjusting the optical length of the resonant cavity of said laser to a length substantially equal to the value L where L is defined by the equation:2nL k1 lambda 1 k2 lambda 2 . . . ki lambda i where k1, k2 . . . ki are whole numbers >0; lambda 1, lambda 2 . . . lambda i are the preselected wavelengths; n is the index of refraction of the resonant cavity; so that a central dip occurs at a point between two peaks of equal amplitude in the most energetic of said power curves associated with said selected beams, utilizing said point as a reference point, monitoring the output of said laser to detect any shift of said dip from said reference point, and further adjusting said optical length so that said dip is maintained at said point.

Claim 3

A method for selectively stabilizing a multifrequency laser at one or more preselected frequencies wherein said laser emits a plurality of beams each having a corresponding frequency, wavelength and power curve, the method comprising selecting at least two of said plurality of beams, adjusting the optical length of the resonant cavity of the laser to a length approximately equal to the value L where L is defined by the equation:2nL k1 lambda 1 k2 lambda 2 . . . kii where k1, k2 . . . ki are whole numbers >0; lambda 1, lambda 2 . . . lambda i are the preselected wavelengths; n is the index of refraction of the resonant cavity; so that said power curves of said selected beams appear at the same time, monitoring the power curve of the most energetic of said selected beams, cyclically modulating the optical lEngth of said resonant cavity, cyclically modulating the laser emission, detecting the phase difference between these two modulations, deriving a signal from said phase difference, using said signal for further adjusting said optical length to an operating point which corresponds to the minimum of a dip appearing in the power curve of said most energetic beam, and regulating by means of said optical length of said resonant cavity for stabilizing said laser at said operating point, whereby said laser is stabilized at said preselected frequencies.

Claim 4

A method for selectively stabilizing a multifrequency laser at one or more preselected frequencies wherein said laser emits a plurality of beams each having a corresponding frequency, wavelength and power curve, the method comprising selecting at least two of said plurality of beams, adjusting the optical length of the resonant cavity of the laser to a length approximately equal to the value L where L is defined by the equation:2nL k1 lambda 1 k2 lambda 2 . . . kii where k1, k2 . . . ki are whole numbers >0; lambda 1, lambda 2 . . . lambda i are the preselected wavelengths; n is the index of refraction of the resonant cavity; so that said power curves of said selected beams appear at the same time, monitoring the power curve of the most energetic of said selected beams, cyclically modulating the optical lEngth of said resonant cavity, cyclically modulating the laser emission, detecting the phase difference between these two modulations, deriving a signal from said phase difference, using said signal for further adjusting said optical length to an operating point which corresponds to the minimum of a dip appearing in the power curve of said most energetic beam, and regulating by means of said optical length of said resonant cavity for stabilizing said laser at said operating point, whereby said laser is stabilized at said preselected frequencies.