US 6,304,584 B1 · Blue diode-pumped solid-state-laser based on ytterbium doped laser crystals operating on the resonance zero-phonon transition

Abstract

The invention provides an efficient, compact means of generating blue laser light at a wavelength near ˜493+/−3 nm, based on the use of a laser diode-pumped Yb-doped laser crystal emitting on its zero phonon line (ZPL) resonance transition at a wavelength near ˜986+/−6 nm, whose fundamental infrared output radiation is harmonically doubled into the blue spectral region. The invention is applied to the excitation of biofluorescent dyes (in the ˜490-496 nm spectral region) utilized in flow cytometry, immunoassay, DNA sequencing, and other biofluorescence instruments. The preferred host crystals have strong ZPL fluorecence (laser) transitions lying in the spectral range from ˜980 to ˜992 nm (so that when frequency-doubled, they produce output radiation in the spectral range from 490 to 496 nm). Alternate preferred Yb doped tungstate crystals, such as Yb:KY(WO4)2, may be configured to lase on the resonant ZPL transition near 981 nm (in lieu of the normal 1025 nm transition). The laser light is then doubled in the blue at 490.5 nm.

Claims42

Dependent claims

A ytterbium-doped solid state laser with an output wavelength in the ˜490-496 nm region, comprising:

a resonant optical cavity;
a ytterbium-doped solid state laser gain medium within said resonant optical cavity;
means for optically pumping said laser gain medium;
an inter-cavity polarizer for forcing said solid state laser gain medium to generate laser light on the zero-phonon-line (ZPL) transition of the 2F5/2−2F7/2 resonance emission band of said gain medium, wherein said inter-cavity polarizer is oriented to allow transmission of polarized light matching the predominant polarization of said ZPL transition of said ytterbium-doped solid state laser gain medium, while providing loss for non-ZPL transitions emitting predominantly in the orthogonal polarization with respect to the polarization of said ZPL of said ytterbium-doped solid state laser gain medium;
and
a nonlinear harmonic doubler crystal for doubling the frequency of said zero-phonon-line (ZPL) transition of the 2F5/2−2F7/2 resonance emission band of said gain medium.

3 more elements

A method for optically pumping a dye solution, comprising:

providing a ytterbium-doped solid state laser gain medium within an optical cavity;
optically pumping said laser gain medium;
forcing said solid state laser gain medium to emit laser light on the zero-phonon-line (ZPL) transition of the 2F5/2−2F7/2 resonance emission band of said gain medium, wherein said step of forcing said solid state laser gain medium to emit laser light on the zero-phonon-line (ZPL) transition is carried out with an inter-cavity polarizer, wherein said inter-cavity polarizer is oriented to allow transmission of polarized light matching the predominant polarization of said ZPL transition of said ytterbium-doped solid state laser gain medium, while increasing the effective losses for nonZPL transitions emitting predominantly in the orthogonal polarization with respect to the polarization of said ZPL of said ytterbium-doped solid state laser gain medium;
doubling the frequency of said zero-phonon-line (ZPL) transition of said 2F5/2−2F7/2 resonance emission band of said gain medium to produce second harmonic light within the wavelength range of 490 nm to 496 nm;
and
directing said second harmonic light onto a dye solution having an excitation band within the wavelength range of 490 nm to 496 nm.

3 more elements

Dependencies are inferred from the claim text.

Blue diode-pumped solid-state-laser based on ytterbium doped laser crystals operating on the resonance zero-phonon transition

Life of this patent

Blue diode-pumped solid-state-laser based on ytterbium doped laser crystals operating on the resonance zero-phonon transition

Life of this patent

Abstract

Claims42