Abstract: A microlaser is disclosed comprising: a gain medium having one face which is adapted be coupled to a source of optical pumping radiation and having an opposite face; harmonic conversion means having a close face which is located adjacent to and spaced apart from the opposite face of the gain medium and which is coated for high transmission at a fundamental and high reflectivity at a harmonic and having an opposite face which is coated for high transmission at the fundamental and some transmission at said harmonic; and polarization control means, located adjacent to and spaced apart from the opposite face of the harmonic conversion means, for controlling the polarization of the fundamental.

Abstract: Optical radiation from a laser diode is frequency modified through interaction with a nonlinear optical material in an external optical cavity. High efficiency frequency modification is achieved through the use of optical feedback from the external cavity to narrow the linewidth of the laser diode output and frequency lock the laser diode to the external cavity.

Abstract: An efficient, compact source of coherent radiation in the infrared, visible and ultraviolet portion of the spectrum which is capable of modulation rates over the range from 0 Hz to in excess of 1 GHz. The radiation is produced by optical mixing within the optical cavity of a laser by introducing input radiation into the optical cavity where: (a) the cavity is that of a diode-pumped solid state laser, and/or (b) input radiation is provided by a solid state device selected from the group consisting of laser diodes, laser diode arrays and diode-pumped solid state lasers.

Abstract: An efficient, compact source of coherent radiation in the infrared, visible and ultraviolet portion of the spectrum which is capable of modulation rates over the range from O Hz to in excess of 1 GHz. The radiation is produced by optical mixing within an external optical cavity wherein at least one of the interacting beams of light is provided by a solid state device selected from the group consisting of laser diodes, laser diode arrays and diode-pumped solid state lasers.

Abstract: A solid state laser is optically pumped by a semiconductive diode. The output facet of the pumping diode is butt-coupled to the input facet of the laser gain medium. The laser gain medium has a short absorption length (<500 um) for the optical pumping radiation such that the pumped mode volume is so small as to support only a single transverse mode of oscillation, i.e., TEM.sub.00 mode operation. In one embodiment a reflector of the laser cavity is formed on the output facet of the pumping diode. In another embodiment the input facet of the laser gain material is bonded to the output facet of the diode pump by means of an index-matching optical cement. The resultant diode pumped laser offers improved frequency stability and reduced size.

Abstract: A microlaser comprises a solid state gain medium, such as YLF or YAG, positioned end to end with a mode selector etalon formed by a fused silica flat, the end of which is adjacent to a planar end of the gain medium is coated with a thin film of nichrome and the other end of which is coated with a multilayer-dielectric partially-transmissive reflector. The other end of the gain medium is curved and coated to be reflective of the laser light and transmissive of the pump light which enters through such end. The thin nichrome film is designed to absorb unwanted modes which have an electric field component at such film while a wanted mode has a null at such film in their standing wave patterns. By substituting birefringent crystalline quartz for the fused-silica, there may be derived emission at two longitudinal modes whose polarization vectors are orthogonal and whose wavelengths are slightly different.

Abstract: A second harmonic, optical generator is disclosed in which a laser diode produces an output pumping beam which is focused by means of a graded, refractive index rod lens into a rod of lasant material, such as Nd:YAG, disposed within an optical resonator to pump the lasant material and to excite the optical resonator at a fundamental wavelength. A non-linear electro-optic material such as MgO:LiNbO.sub.3 is coupled to the excited, fundamental mode of the optical resonator to produce a non-linear interaction with the fundamental wavelength producing a harmonic. In one embodiment, the gain medium and the non-linear material are disposed within an optical resonator defined by a pair of reflectors, one of which is formed on a face of the gain medium and the second of which is formed on a face of the non-linear medium. In another embodiment, the non-linear, electro-optic material is doped with the lasant ion such that the gain medium and the non-linear doubling material are co-extensive in volume.