摘要:
The present invention relates to a solid state laser device with a solid state gain medium between two resonator end mirrors (3, 5) and a GaN-based pump laser (1) arranged to optically pump the solid state gain medium. The solid state gain medium is a Pr 3+ -doped crystalline or polycrystalline host material (4) which has a cubic crystalline structure and highest phonon energies of ≤ 600 cm -1 and provides a band gap of ≥ 5,5 eV. The proposed solid state laser can be designed to emit at several visible wavelengths with the emitted power showing a reduced dependence on the temperature of the GaN-based pump laser (1).
摘要:
The invention relates to an apparatus (1) for determining a flow property of a fluid (2). The apparatus comprises a distance and velocity determination unit (3) for determining distances of elements of the fluid to the distance and velocity determination unit (3) and for determining velocities of the elements at the same time based on a self-mixing interference signal. The apparatus (1) comprises further a flow determination unit (4) for determining the flow property of the fluid (2) based on at least one of the determined distances and velocities. This allows determining the flow property, even if the fluid (2) is optically thick.
摘要:
The present invention relates to a method of switching laser emission of a solid state laser between different emission wavelengths, said different emission wavelengths being based on different electronic transitions in a solid state laser medium (3) of the solid state laser. The at least two end mirrors (1, 2) of the solid state laser are designed to allow lasing of the laser at the different emission wavelengths and coupling out of the different emission wavelengths at one end mirror (2) of the laser cavity. The switching of the laser emission is achieved by switching the cavity length of the laser cavity between different cavity lengths, wherein the different cavity lengths are selected such that at each of the cavity lengths the solid state laser lases at only one of the different emission wavelengths which is different from the emission wavelengths at the other of the selected cavity lengths. With the method and corresponding device an easy switching between emission wavelengths of a solid state laser is possible.
摘要:
A system is described which enables parameters of a tire (20) to be measured by means of self-mixing laser interferometry. Laser sensors (1) using self- mixing laser interferometry can measure distances and/or speed of surface elements of a tire (20). Consequently, a system comprising such a laser sensor (1) can for example be used to measure and indicate tire tread wear, tire load or speed. In comparison with laser sensor based systems using the well-known time of flight method, the described system is simple, cost effective and, due to the small size of the laser sensor (1), can easily be integrated in cars.
摘要:
The present invention relates to a switchable dual wavelength solid state laser with a solid state gain medium (1) which is selected to emit optical radiation at a first wavelength with a first polarization and of at least a second wavelength with a second polarization different from said first polarization when optically or electrically pumped. A polarizing device (7) is arranged within the laser cavity, said polarizing device (7) being adjustable at least between said first and said second polarization. The two end mirrors (2, 3) of the laser cavity are designed to allow lasing of the solid state laser at the first wavelength when the polarizing device (7) is adjusted to the first polarization, and to allow lasing of the solid state laser at the second wavelength when the polarizing device (7) is adjusted to the second polarization. The proposed solid state laser allows an easy switching between two emission wavelengths. The polarizing device (7) is for example realized by a combination of a Pockels cell (8) and a polarizer (9). End mirrors (2, 3) suppress unwanted wavelengths and a beam clump (10) absorbs the radiation not fed-back in the resonator.