摘要:
The invention relates to an optical amplifying medium comprising a liquid medium, having an organic ligand corresponding to the following chemical formula: the groups R1, R2 and R3 comprising halogenated chains and a rare earth ion. The advantage of using a liquid medium lies in the possibility of more easily discharging the heat within the amplifying medium. The present solution provides a formulation that furthermore makes it possible to have entities that are non-toxic contrary to those proposed in the prior art.
摘要:
The invention relates a power fiber laser system including at least one single-mode fiber laser, emitting at a signal wavelength, the fiber including at least one outer cladding and a core, in which the core of the fiber has a radially graded index. The fiber includes, at least over a part of its length, a geometrical section having a graded fiber-core radius that decreases between an input end of the section and an output end of the section, the core radius and the index variation between the cladding and the fiber at the input end being such that the normalized frequency at the signal wavelength is less than the normalized cutoff frequency at which the fiber becomes unimodal.
摘要:
The field of the invention is that of solid-state laser gyros used in inertial control units. However, there are certain technical difficulties in producing laser gyros of this type that are due partly to the fact that the counterpropagating waves interfere with each other in the amplifying medium. A laser gyro according to the invention comprises at least one solid-state amplifying medium and an optical ring cavity comprising first optical means for imposing a first linear polarization state common to the two counterpropagating optical waves at the entrance and exit of the zone containing the amplifying medium and second optical means for imposing, within the amplifying medium, a second linear polarization state on the first optical wave and a third linear polarization state on the second optical wave, these polarization states being perpendicular. Thus, all the drawbacks associated with interference are eliminated.
摘要:
The field of the invention is that of solid-state laser gyros. One of the major inherent problems in this technology is that the optical emission of this type of laser is by nature highly unstable in terms of power. To reduce this instability, the invention proposes to introduce, into the cavity, optical gains controlled by the installation of an optical assembly comprising an anisotropic lasing medium, a first optical element and a second optical element exhibiting a nonreciprocal effect, each acting on the polarization of the counterpropagating optical modes, at least one of these two effects being variable, thus making it possible to introduce controlled optical gains that depend on the propagation direction of the counterpropagating optical modes. Several devices are described and employ either fixed effects of the element that are combined with variable nonreciprocal effects, or the reverse. These devices apply in particular to monolithic-cavity lasers.
摘要:
The invention relates to a laser active optronic system with improved detectivity, especially an eye-safe optronic system. The system comprises a channel for the emission by an emission source of a laser beam illuminating a target and a channel for receiving the wave backscattered by the target. An optical switching device is positioned in the receive channel, said optical switching device receiving said backscattered wave and comprising an optical gain medium and pumping means for pumping said gain medium, said gain medium being absorbent at the wavelength of the laser and becoming substantially transparent when it is pumped, in such a way as to allow the switching device to be actuated in the on mode or off mode respectively. It further includes a control unit for controlling the pumping means, allowing the switching device to be actuated in the on mode in at least one temporal window of predetermined duration, triggered at a predetermined instant after the start of emission of the illuminating laser beam.
摘要:
The invention concerns solid-state gyrolasers used to measure rotation speeds or relative angular positions. This type of equipment is used, in particular, in aeronautical applications. The purpose of the invention is to complete the optic devices required to control the instability of lasers, using specific optic devices that eliminate the blind region. In this way, a “fully optic” solid-state laser is obtained, without moving parts, stable, and without blind regions. These devices comprise in particular reciprocal and nonreciprocal optical rotators, arranged so that two counter-propagating optical modes travel in the cavity at sufficiently different frequencies to avoid mode locking.
摘要:
An unstable optical cavity for laser beams, having at least 3 deflection means for making a beam created in the cavity undergo at least three changes in direction so to form an optical ring path, and an optical magnification set disposed among the deflecting means. The at least 3 deflection means are prisms, each of which has an air-glass reflecting interface that provides one of the changes in direction by total reflection. A first of the at least 3 prims is positioned at an output of the cavity and has an air-glass reflecting interface with an insufficient size for a total reflection of the beam in the cavity, and remaining ones of the prisms have an air-glass reflecting interface with a sufficient size for a total reflection of the beam in the cavity.
摘要:
Disclosed is a non-linear optical device in which the non-linear medium comprises a circular surface on which the light beam to be processed gets reflected. A structure such as this can be used to resolve the difficulties of making mirrors of the cavity containing the non-linear medium.
摘要:
A laser includes a gas enclosure placed in an optical cavity and receiving a pump beam to generate at least one first-order and one second-order Stokes wave. One of the mirrors of the cavity is transparent to wavelengths which are higher than the first-order Stokes wave.
摘要:
The field of the invention is that of solid-state laser gyros used for the measurements of rotation speed or relative angular positions. This type of equipment is notably used for aeronautical applications. The object of the invention is to complete the optical devices necessary to control the instability of lasers by specific optical devices enabling elimination of the dead zone and of population inversion gratings exiting in the amplifying medium. An “all optical” solid-state laser is hence obtained without moveable parts, stable and without a dead zone. To this end, the laser gyro according to the invention comprises notably and optical assembly enabling a nonreciprocal optical phase-shift to be introduced between the counterpropagating modes; and control means allowing the phase-shift amplitude to be varied periodically around a mean value that is very approximately zero.