摘要:
A system and method for improving spatial light modulator (SLM) devices such as Surface Acoustic Wave (SAW) modulators are disclosed. The SAW modulators can improved angular bandwidth and suppress unwanted diffractive orders. In one example, a coating layer(s) is applied to a proximal face of the SAW modulator to improve coupling of guided modes into leaky modes. Additionally, applying coating layers(s) such as a hybrid anti-reflective/highly reflective coating to an exit face of the SAW modulator can suppress transmission of undesired diffractive order(s).
摘要:
Procédé et système (1) d'imagerie acousto-optique d'une zone d'observation (3) d'un milieu (2). Le système comprend un dispositif d'acquisition (11) comportant un réseau de transducteurs (4) pour générer une pluralité d'ondes acoustiques non-focalisées, un dispositif d'émission lumineuse (8) pour émettre une onde lumineuse incidente et générer des ondes lumineuses marquées comportant une composante acousto-optique décalée en fréquence par les ondes acoustiques non-focalisées, et un détecteur (9) pour acquérir des signaux de mesure (S). Le système comporte en outre un dispositif de traitement (12) pour déterminer une intensité lumineuse (I) dans la zone d'observation (3) à partir des signaux de mesure (S).
摘要:
This laser light-source apparatus comprises: fiber amplifiers 20, 30 and a solid-state amplifier 50 that amplify pulse light output from a seed light source 10 that is a first light source; non-linear optical elements 60, 70 that convert the wavelength of pulse light output from the solid-state amplifier; an optical switch element 40 that allows or blocks the propagation of pulse light from the fiber amplifiers to the solid-state amplifier; a second light source 11 that is disposed upstream of the solid-state amplifier, and the light from which can be combined with the pulse light output from the seed light source; and a control unit 100 that at least controls the optical switch element 40 so as to block the propagation of light during the output of pulse light from the seed light source 10, and controls the oscillation of the second light source 11. It is thus possible to temporarily stop the output of pulse light without stopping an excitation light source, and avoid a reduction in beam propagation characteristics immediately after output is restarted.
摘要:
The invention relates to an acousto-optic deflector comprising a bulk of acousto-optic medium and acoustic wave generator coupled to the bulk, characterised by that the acoustic wave generator comprises at least two different electro-acoustic transducers for generating acoustic waves in the bulk.
摘要:
Es wird ein Kurzpuls-Laser (1) mit einem Seed-Laseroszillator (2), mit einem steuerbaren Pulspicker (4) zum Auskoppeln eines Laserpulses oder einer Sequenz von Laserpulsen und mit einer dem Pulspicker (4) nachgeschalteten Verstärkereinheit (5, 6) zum Verstärken der ausgekoppelten Laserpulse angegeben, wobei die Verstärkereinheit (5, 6) wenigstens eine erste Verstärkerstufe (5) und einen steuerbaren ersten Pumplaser (8) umfasst. Dabei ist weiter eine Steuereinheit (10) umfasst, die eingerichtet ist, den Pulspicker (4) und/oder den ersten Pumplaser (8) zum Erreichen einer vorgegebenen Energie der nachverstärkten Laserpulse zu steuern.
摘要:
A photoelastic modulator (PEM) has two parts (11, 13) of the same or dissimilar cross sections, joined together to form an abrupt junction (16). A transducer, for which the natural oscillation is at the half acoustic wavelength mode, excites a longitudinal standing wave of high purity in the PEM. A feedback system is used to achieve stable phase synchronisation of multiple PEMs working at the same oscillation frequency, where the outputs of an amplitude and phase sensor for one PEM is used to correct phase variations of other PEMs and to compensate optical retardation errors.
摘要:
An element for steering electromagnetic beams. The element includes a phase change material in combination with dielectric and other layers in a multilayer optical stack. The phase change material that is reversibly transformable between two or more structural states, where different structural states differ with respect to refractive index and/or extinction coefficient. The structural state of the phase change material establishes a phase angle state for the element that dictates the direction of propagation of an output beam produced from an incident electromagnetic beam. Depending on the structural state, the element adopts one of two principal phase angle states and a binary beam steering capability is achieved in which an incident electromagnetic beam can be redirected in either of two directions. In a preferred embodiment, the output beam is a reflected beam and the element includes a phase change material sandwiched between two dielectric materials and supported by a metal layer.
摘要:
Electromagnetic radiation is input into a photonic crystal having a shock wave propagating within, wherein interactions between the shock wave and the incident electromagnetic radiation provide for the modification of frequency and bandwidth associated with input electromagnetic radiation. Modifications in frequency of the electromagnetic radiation are on the order of the gap size with 100% efficiency in some cases. Additionally, the bandwidth associated with the electromagnetic radiation is increased or decreased by orders of magnitude based on such interactions. High amplitudes are trapped at the shock front for a controllable period of time, allowing for the controlled manipulation of pulses of light. Lastly, the incorporation of deliberately designed crystal defects and non-linear materials results in the conversion of all the energy in the defect band upwards in frequency if the highest group velocity is less than the shock wave speed.