摘要:
Disclosed is a semiconductor laser device capable of minimizing the spot diameter of a laser light and also capable of improving the transmittance of light passing through a fine aperture. The semiconductor laser device comprises a light absorption film provided with a fine aperture on the outside of the light-emitting surface of the semiconductor laser element. The aperture is formed such that the aperture width W1 in a direction parallel to the polarizing direction of the laser light is smaller than half the oscillation wavelength of the semiconductor laser element, and the aperture width W2 in a direction perpendicular to the polarizing direction is larger than the aperture width W1.
摘要:
Disclosed is a semiconductor laser device capable of minimizing the spot diameter of a laser light and also capable of improving the transmittance of light passing through a fine aperture. The semiconductor laser device comprises a light absorption film provided with a fine aperture on the outside of the light-emitting surface of the semiconductor laser element. The aperture is formed such that the aperture width W1 in a direction parallel to the polarizing direction of the laser light is smaller than half the oscillation wavelength of the semiconductor laser element, and the aperture width W2 in a direction perpendicular to the polarizing direction is larger than the aperture width W1.
摘要:
At an n--n hetero-interface in a GaN-based or ZnSe-based multilayered semiconductor laser and light-emitting diode, an excessive voltage drop causing the operating voltage to increased is reduced, thereby lengthening the service life of the device. A single or plurality of n-type intermediate layers are provided in the n--n hetero-interface region where the excessive voltage drop develops. The excessive voltage drop developing at the n--n hetero-interface is decreased by setting the energy value at the edge of the conduction band of each intermediate layer to a mid-value between the energy values at the edges of the conduction bands of the n-type compound semiconductors adjoining both sides of the intermediate layer. The configuration of a GaN-based MQW laser including the intermediate layer formed on sapphire substrate is shown. The relationship between the lattice constant of an intermediate layer necessary for obtaining an intermediate layer excellent in crystallinity suitable for the above object and the lattice constants of compound semiconductors adjoining both sides of the intermediate layer is described.
摘要:
An optical wavelength-converting device for generating the second-harmonic wave through Cerenkov radiation has a substrate made from nonlinear optical crystal which acts as a cladding layer. Formed on the top surface of the substrate is a long, narrow optical waveguide layer, whose refractive index is larger than that of the substrate. In the substrate, multi-layered domain-inverted sections are formed. With this arrangement, the nonlinear coefficient is locally changed, thereby compensating for phase mismatching between the fundamental wave and the second-harmonic wave in the direction perpendicular to the substrate's surface. This compensation helps improve the efficiency in converting the laser input light of the fundamental wave into the second-harmonic wave.
摘要:
A light emitting device includes a light emitting element emitting an excitation light and a fluorescent element. The fluorescent element includes a semi-translucent film facing the light emitting element, and transmits the excitation light; a first luminescent film including phosphors to absorb the excitation light transmitted through the semi-translucent film and to emit a visible light having a different wavelength than the excitation light; and a reflection film disposed on an opposite side of the first luminescent film on which the semi-translucent film is disposed, reflecting the excitation light transmitted through the first luminescent film towards the first luminescent film.
摘要:
This invention provides a light-emitting element that comprises a light-emitting portion made of a nitride semiconductor; and a first wavefront converter for converting the radiated shape of light that is emitted from the light-emitting portion into a radiated shape that is smaller than the wavelength thereof, and emitting the same as output light. In this case, the first wavefront converter has a small aperture of a diameter that is smaller than the wavelength of light that is emitted from the light-emitting portion. If the output light is made to comprise an evanescent wave that is emitted to the exterior through this small aperture, it is possible to obtain an extremely small light spot. This invention also relates to a surface-emitting type of light-emitting element comprising a multi-layered structure comprising a light-emitting layer; and a pair of electrodes for supplying a current to the light-emitting layer; wherein output light is emitted from a light-emitting surface on top of the multi-layered structure; and the pair of electrodes are recessed from the light-emitting surface to the light-emitting layer side. This makes it possible to bring the light-emitting surface extremely close to an object to be illuminated. The small aperture can be opened up in a self-aligning manner by using the light from the light-emitting portion. As a result, it is possible to provide a light-emitting element and a method of fabrication thereof that create beam characteristics that are suitable for use with an optical disc or the like.
摘要:
Disclosed is a long-life GaN-based semiconductor device which is achieved by reducing the operating voltage of the semiconductor device comprising a GaN-based or a ZnSe-based compound semiconductor formed on a sapphire substrate and by preventing the electromigration of metal atoms from an electrode into compound semiconductor layers. The operating voltage of the GaN-based or ZnSe-based semiconductor device formed on a sapphire substrate or a SiC substrate can be greatly reduced by employing a ZnO layer doped with a significant amount of Al as a material for forming ohmic contact to p- or n- compound semiconductor layers. The long-life GaN-based semiconductor device can be attained by preventing electromigration of atoms from a metallic electrode by use of ZnO layer. If a superlattice including the ZnO layer is employed as an optical guide layer or if the superlattice including the ZnO layer as an active layer, a long-life laser diode with a low operating voltage and a wide wavelength range can be obtained.
摘要:
At an n--n hetero-interface in a ZnSe-based or GaN-based multilayered semiconductor laser and light-emitting diode, an excessive voltage drop causing the operating voltage to increased is reduced, thereby lengthening the service life of the device. A single or plurality of n-type intermediate layers are provided in the n--n hetero-interface region where the excessive voltage drop develops. The excessive voltage drop developing at the n--n hetero-interface is decreased by setting the energy value at the edge of the conduction band of each intermediate layer to a mid-value between the energy values at the edges of the conduction bands of the n-type compound semiconductors adjoining both sides of the intermediate layer. The configuration of a GaN-based MQW laser including the intermediate layer formed on sapphire substrate is shown. The relationship between the lattice constant of an intermediate layer necessary for obtaining an intermediate layer excellent in crystallinity suitable for the above object and the lattice constants of compound semiconductors adjoining both sides of the intermediate layer is described.
摘要:
A semiconductor laser device includes a substrate, a first cladding layer formed on the substrate, an active layer formed on the first cladding layer, and a second cladding layer formed on the active layer having a conductivity type different from that of the first cladding layer, wherein at least one of the first and second cladding layers has a multiquantum barrier structure. The width of the first quantum barrier of the multiquantum barrier structure relative to the side of the active layer is 24 to 100 nm, the width of the second quantum barrier of the multiquantum barrier structure relative to the side of the active layer is 5 to 20 nm, and the multiquantum barrier structure is constituted by alternately stacking first thin layers consisting of In.sub.z (Ga.sub.1-x Al.sub.x).sub.1-z P (x is 0.7 to 1.0 and z is 0 to 1.0) and second thin layers consisting of In.sub.z (Ga.sub.1-y Al.sub.y).sub.1-z P (y is 0 to 0.3 and z is 0 to 1.0).
摘要:
According to the present invention, there is provided a semiconductor light-emitting device including a light-emitting layer having a first semiconductor layer, and formed on a main surface of one side of a semiconductor substrate, an upper-most layer of the light-emitting layer made of a compound semiconductor containing elements from the group II and group VI of the periodic table, the second semiconductor layer formed on the first semiconductor layer, and made of a material having a lattice constant different from that of the material of the semiconductor substrate by at least 2%, the second semiconductor layer having a film thickness of a critical film thickness, the first electrode formed on a main surface of the other side of the semiconductor substrate, and the second electrode formed on the second semiconductor layer.