摘要:
This invention provides a penicillin derivative of the formula and a salt thereof ##STR1## wherein X represents chlorine atom or bromine atom and R represents hydrogen atom or penicillin carboxy-protecting radical, and a process for preparing the derivative of the formula (I) and a salt thereof by reacting a compound of the formula ##STR2## wherein R is as defined above with a chlorinating reagent or brominating reagent and, when required, forming a salt thereof.
摘要:
A laser diode which realizes NFP with a stable and uniform shape. The laser diode includes, on a semiconductor substrate, an active layer, one or a plurality of strip-shaped current confinement structures confining a current which is injected into the active layer, and a stacked structure including one or a plurality of strip-shaped convex portions extending in an extending direction of the current confinement structure.
摘要:
This semiconductor laser device has the same structure as the conventional broad-area type semiconductor laser device, except that both side regions of light emission areas of active and clad layers are two-dimensional-photonic-crystallized. The two-dimensional photonic crystal formed on both side regions of the light emission area is the crystal having the property that 780 nm laser light cannot be wave-guided in a resonator direction parallel to a striped ridge within the region. The light traveling in the direction can exist only in the light emission area sandwiched between two photonic crystal regions, which results in the light laterally confined by the photonic crystal region. The optical confinement of the region suppresses the loss in the light at both edges of the stripe serving as the boundary of the optical confinement, which reduces the curve of wave surface and uniforms the light intensity distributions of NFP and FFP.
摘要:
This semiconductor laser device has the same structure as the conventional broad-area type semiconductor laser device, except that both side regions of light emission areas of active and clad layers are two-dimensional-photonic-crystallized. The two-dimensional photonic crystal formed on both side regions of the light emission area is the crystal having the property that 780 nm laser light cannot be wave-guided in a resonator direction parallel to a striped ridge within the region. The light traveling in the direction can exist only in the light emission area sandwiched between two photonic crystal regions, which results in the light laterally confined by the photonic crystal region. The optical confinement of the region suppresses the loss in the light at both edges of the stripe serving as the boundary of the optical confinement, which reduces the curve of wave surface and uniforms the light intensity distributions of NFP and FFP.
摘要:
This semiconductor laser device has the same structure as the conventional broad-area type semiconductor laser device, except that both side regions of light emission areas of active and clad layers are two-dimensional-photonic-crystallized. The two-dimensional photonic crystal formed on both side regions of the light emission area is the crystal having the property that 780 nm laser light cannot be wave-guided in a resonator direction parallel to a striped ridge within the region. The light traveling in the direction can exist only in the light emission area sandwiched between two photonic crystal regions, which results in the light laterally confined by the photonic crystal region. The optical confinement of the region suppresses the loss in the light at both edges of the stripe serving as the boundary of the optical confinement, which reduces the curve of wave surface and uniforms the light intensity distributions of NFP and FFP.
摘要:
The present invention provides a semiconductor laser including a plurality of light emission portions provided on the same substrate, each of which is adapted to emit laser beams with a multi-mode. A part of the plurality of light emission portions constitute a main light emission group, and the rest of the plurality of light emission portions constitute a sub-light emission group. A main electrode for supplying a current to the main light emission group and a sub-electrode for supplying a current to the sub-light emission group are separately provided. With this configuration, it is possible to keep the entire quality of laser beams of the semiconductor laser constant.
摘要:
A semiconductor light emitting device capable of correcting astigmatism difference well and oscillating stably also at the time of a high output operation, wherein a waveguide stripe width at the center of a stripe portion is constant, an inter-ridge recessed portion width (ridge separation width) is set narrow at the center portion of the stripe portion (resonator center portion), and a ridge separation width near an end surface side is set broader than the ridge separation width at the center portion, whereby a waveguide mode of the stripe center portion is laterally spread and in addition the current can be held in the narrow region and, accordingly, a saturable absorbing region is formed in the lateral region inside an active layer, pulsation can be stably induced, and an effective refractive index difference An near the end surface is made large and an index guide-like waveguide can be obtained, whereby astigmatism difference can be reduced to close to zero.
摘要:
A novel antibiotic substance and derivatives thereof, having strong antibiotic activity and .beta.-lactamase inhibiting effect and a method for producing the same by aerobic cultivation of Streptomyces A 271.
摘要:
A vibration detection device that includes a light source that emits a laser beam; an interferometer, which includes two vibrating bodies that are capable of reflecting the laser beam, that splits the laser beam to cause interference patterns; and a detector that detects vibrations on the basis of the interference patterns.
摘要:
A laser diode capable of effectively inhibiting effects of feedback light is provided. A laser diode includes a substrate, and a laminated structure including a first conductive semiconductor layer, an active layer having a light emitting region, and a second conductive semiconductor layer having a projecting part on the surface thereof, on the substrate, wherein a feedback light inhibition part is provided on a main-emitting-side end face, and effects of feedback light in the vicinity of lateral boundaries of the light emitting region are inhibited by the feedback light inhibition part.