Energy converter, surface laser and methods for their operation

Claim 1

In a surface laser, a medium having a high absorption transition from a ground state to an excited state, and possessing a third state to which radiative decay takes place to define a fluorescent radiative transition in response to being excited with radiation of a particular wavelength corresponding to said absorption, said medium having low losses between said excited and third states except for said radiative transition, pump means forming a monochromatic output beam to couple to said absorption transition, said output beam being directed into the surface of said medium for optically pumping said medium from the ground state into said excited state, the high absorption transition probability resulting in complete absorption of said pump beam within a small volume of said medium, said medium having a first, surface mode of laser oscillation lying parallel to the input surface thereof and in alignment with a major transverse axis of the region excited by said pump beam, and a second, penetration mode in alignment with the major dimension of the volume excited by said pump beam, said penetration mode being threshold activated when the intensity of the pump beam produces a depth of penetration within said media greater than the transverse extent of said beam at said input surface.

Claim 7

A method for changing the output mode and direction of a laser of the type employing a medium having a high concentration of active centers possessing a well defined upper state and at least one lower state defining a fluorescent radiative transition when excited with pump radiation of a particular wavelength, said medium having a high coefficient of efficiency, the steps of pumping said medium with a laser beam having an output frequency capable of being absorbed to excite active centers in said medium into said upper state, the high concentration of active centers resulting in nearly complete absorption of the pump laser beam within a small depth within said medium, maintaining the intensity of radiation of said pump laser beam on said medium at a level sufficient to excite the surface laser with an action having an output beam line parallel to the input surface of said media at the region of excitation to thereby obtain a first mode of laser output from said media, increasing the intensity of exciting radiations above said threshold whereby the depth of penetration of the pump medium in said media exceeds the greatest lateral extent of said beam whereupon said laser media step shifts into a second mode having an output beam in alignment with the excited region, depth and direction.

Claim 8

A method for changing the output mode and direction of a laser of the type employing a medium having a high concentration of active centers possessing a well defined upper state and at least one lower state defining a fluorescent radiative transition when excited with pump radiation of a particular wavelength, said medium having a high coefficient of efficiency, the steps of pumping said medium with a laser beam having an output frequency capable of being absorbed to excite active centers in said medium into said upper state, the high concentration of active centers resulting in nearly complete absorption of the pump laser beam within a small depth within said medium, maintaining the intensity of radiation of said pump laser beam on said medium at a level sufficient to excite the surface laser with an action having an output beam line parallel to the input surface of said media at the region of excitation to thereby obtain a first mode of laser output from said media, increasing the intensity of exciting radiations above said threshold whereby the depth of penetration of the pump medium in said media exceeds the greatest lateral extent of said beam whereupon said laser media step shifts into a second mode having an output beam in alignment with the excited region, depth and direction.