Claims
- 1. An optically pumped laser oscillator or amplifier, comprising:
a laser head including a gain medium exhibiting polarization-dependent absorption along two crystallographic axes; a pump source producing a pump beam characterized in that the medium's absorption coefficients along both said crystallographic axes are equal or the difference between the absorption coefficients relative to the lowest absorption coefficient R=Abs(αc−αa)/(min(αc,αa)) is reduced at least by a factor of two compared to the same relative difference between the two absorption coefficients at the medium's absorption peaks, used for conventional pumping either by pumping with unpolarized or partially polarized pump light at a wavelength around which the average absorption coefficients along both of said crystallographic axes are equal or present a relative difference that is reduced by a factor of two or better compared to conventional pumping around the medium's absorption peaks or by pumping with a combination of two pump sources emitting light at different wavelengths and of orthogonal polarizations, each of the pump sources emitting at a wavelength for which the absorption coefficients on their respective crystallographic axes are equal or present a relative difference that is reduced by a factor of two or better compared to conventional pumping around the medium's absorption peaks.
- 2. The oscillator or amplifier of claim 1, wherein the pump light is emitted by laser diode(s) and delivered to the gain medium through a non-polarization-maintaining device.
- 3. The oscillator or amplifier of claim 1, wherein the pump light is emitted by laser diodes whose beams are combined by means of polarizing elements.
- 4. The oscillator or amplifier of claim 1, wherein the gain medium is a Neodymium-doped Vanadate (Nd:YVO4) crystal and the pump center wavelength is 819±4 nm.
- 5. The oscillator or amplifier of claim 1, wherein the gain medium is a Neodymium-doped Vanadate (Nd:YVO4) crystal and the pump center wavelength is 888±4 nm.
- 6. The oscillator or amplifier of claim 1, wherein the gain medium is a Neodymium-doped Vanadate (Nd:YVO4) crystal longer than 15 mm.
- 7. The oscillator or amplifier of claim 1, wherein the gain medium is end-pumped, i.e. the pump and laser radiations travel through the crystal with close to parallel directions.
- 8. A method of pumping laser materials having polarization-dependent absorption along two crystallographic axes with a pump beam characterized in that the medium's absorption coefficients along both said crystallographic axes are equal or
the difference between the absorption coefficients relative to the lowest absorption coefficient R=Abs(αc−αa)/(min(αc,αa)) is reduced at least by a factor of two compared to the same relative difference between the two absorption coefficients at the medium's absorption peaks, used for conventional pumping either by pumping with unpolarized or partially polarized pump light at a wavelength around which the average absorption coefficients along both of said crystallographic axes are equal or present a relative difference that is reduced by a factor of two or better compared to conventional pumping around the medium's absorption peaks or by pumping with a combination of two pump sources emitting light at different wavelengths and of orthogonal polarizations, each of the pump sources emitting at a wavelength for which the absorption coefficients on their respective crystallographic axes are equal or present a relative difference that is reduced by a factor of two or better compared to conventional pumping around the medium's absorption peaks.
Priority Claims (1)
Number |
Date |
Country |
Kind |
03 012 451.5 |
May 2003 |
EP |
|
REFERENCES CITED
[0001] US Patent Documents
16,185,235June 2001Cheng et al.5,9991544July 1999Petersen6,137,820October 2000Maag et al.6,144,484July 2000Marshall
[0002] Other Publications
[0003] Dudley, Hodgson, Hoffman, Kopper, “Direct 880 nm Diode-pumping of Vanadate Lasers”, CTuI3, CLEO 2002