Hamamatsu-photonics K.k.

Hamamatsu Photonics Kabushiki Kaisha

Minoru Niigaki

Toru Hirohata

Masami Yamada

Hirofumi Kan

Shoichi Uchiyama

Kazutoshi Nakajima

Yasufumi Takagi

Tomoko Mochizuki

Tomoko Suzuki

Hiroyasu Fujiwara

Minoru Kondo

Akira Higuchi

Tuneo Ihara

Itaru Mizuno

Tadataka Edamura

Katsuyuki Kinoshita

Yasuharu Negi

Tokuaki Nihashi

Kuniyoshi Mori

Masashi Ohta

Kazuue Fujita

Yoshihiko Mizushima

Yasuyuki Egawa

Yujin Zheng

Koichiro Oba

Kenichi Sugimoto

Toshihiro Suzuki

Norio Asakura

Nobuharu Suzuki

Wataru Akahori

Yoshitaka Suzuki

Tsuneo Ihara

You Wang

A photodetectorA comprises a multilayer structurehaving a first layerconstituted by first metal or first semiconductor, a semiconductor structure layermounted on the first layerand adapted to excite an electron by plasmon resonance, and a second layermounted on the semiconductor structure layerand constituted by second metal or second semiconductor.

Photodetector

When light is incident to an antenna layer AAof a photocathode AA, light of a specific wavelength included in the incident light couples with surface plasmons in the antenna layer AAwhereupon near-field light is outputted from a through hole AA. The intensity of the output near-field light is proportional to and greater than the intensity of the light of the specific wavelength. The output near-field light has a wavelength that can be absorbed in a photoelectric conversion layer AA. The photoelectric conversion layer AAreceives the near-field light outputted from the through hole AA. A region of the photoelectric conversion layer AAaround the through hole AAabsorbs the near-field light and generates photoelectrons (e) in an amount according to the intensity of the near-field light. The photoelectrons (e) generated in the photoelectric conversion layer AAare outputted to the outside.

Photocathode, electron tube, field assist type photocathode, field assist type photocathode array, and field assist type electron tube

A light-emitting body of rapid speed of response and high light emission intensity, and an electron beam detector, scanning electron microscope and mass spectroscope using this are provided. In the light-emitting bodyaccording to the present invention, when fluorescence is emitted by a nitride semiconductor layerformed on one faceof a substratein response to incidence of electrons, at least some of this fluorescence is transmitted through this substrate, whereby that fluorescence is emitted from the other faceof the substrate. The response speed of this fluorescence is not more than &#x3bc;sec order. Also, the intensity of emission of this fluorescence is almost identical to that of a conventional P47 phosphor. Specifically, with this light-emitting body, a response speed and light emission intensity are obtained that are fully satisfactory for application to a scanning electron microscope or mass spectroscope. In addition, a cap layercontributes to improvement in the persistence rate of light emission in the nitride semiconductor layer, so, with this light-emitting body, not only high-speed response and high light emission intensity are obtained, but also an excellent persistence rate.

Luminous body, electron beam detector using the same, scanning electron microscope, and mass analysis device

A semiconductor photocathodeincludes: a transparent substrate; a first electrode, formed on the transparent substrateand enabling passage of light that has been transmitted through the transparent substrate; a window layer, formed on the first electrodeand formed of a semiconductor material with a thickness of no less than 10 nm and no more than 200 nm; a light absorbing layer, formed on the window layer, formed of a semiconductor material that is lattice matched to the window layer, is narrower in energy band gap than the window layer, and in which photoelectrons are excited in response to the incidence of light; an electron emission layer, formed on the light absorbing layer, formed of a semiconductor material that is lattice matched to the light absorbing layer, and emitting the photoelectrons excited in the light absorbing layerto the exterior from a surface; and a second electrode, formed on the electron emission layer.

Photocathode comprising a plurality of openings on an electron emission layer

When to-be-detected light is made incident from a support substrateside of a photocathode E, a light absorbing layerabsorbs this to-be-detected light and produces photoelectrons. However, depending on the thickness and the like of the light absorbing layerthe to-be-detected light can be transmitted through the light absorbing layerwithout being sufficiently absorbed by the light absorbing layerThe to-be-detected light transmitted through the light absorbing layerreaches an electron emitting layerA part of the to-be-detected light that has reached the electron emitting layerproceeds toward a through-holeof a contact layerSince the length dof a diagonal line of the through-holeis shorter than the wavelength of the to-be-detected light, the to-be-detected light can be suppressed from passing through the through-holeand being emitted to the exterior. The to-be-detected light suppressed from being externally emitted is reflected on the exposed surface of the electron emitting layerand is again made incident into the light absorbing layerto be absorbed. Thereby, a photocathode excellent in light detection sensitivity is realized.

Photocathode

A transmission type photocathode includes a light absorption layerformed of diamond or a material containing diamond as a main component, a supporting framefor reinforcing the mechanical strength of the light absorption layer, a first electrodeprovided at the plane of incidence of the light absorption layer, and a second electrodeprovided at the plane of emission of the light absorption layer. A voltage is applied between the plane of incidence and plane of emission of the light absorption layerto form an electric field in the light absorption layer. When light to be detected is made incident and photoelectrons occur in the light absorption layer, the photoelectrons are accelerated to the plane of emission by the electric field formed in the light absorption layer, and emitted to the outside of the transmission type photocathode.

Transmission type photocathode including light absorption layer and voltage applying arrangement and electron tube

An alkali-encapsulated cell internally having an alkali metal vapor G encapsulated is provided with first and second heaters. The alkali-encapsulated cellhas first and second end facesopposed to each other, and a side faceconnecting the two end faces. Each of the first and second heatershas a covering portionB,B and an extending portionC,C. Some portions of the alkali-encapsulated cellare inserted in the covering portionsB,B. On the other hand, the extending portionsC,C extend in directions away from the alkali-encapsulated cell. The first and second heatersare separated from each other with a distance dbetween them in an opposing direction of the first and second end faces

Heater-attached alkali-encapsulated cell and alkali laser apparatus

When light is made incident into antenna layers, andof a photodetector, specific wavelength components of light contained in the incident light combine with surface plasmons of the antenna layers, and, and surface plasmon resonance occurs. Thereby, near-field lights are outputted from through-holesof the antenna layers, and. The near-field light outputted from each through-holereaches a light absorbing layervia light receiving surfaces, and. The light absorbing layergenerates a charge of an amount according to the amount of received light. Since cycle intervals &#x39b;a, &#x39b;b, and &#x39b;c of convex portionsin the antenna layers, andare different from each other, the wavelength component of light that combines with a surface plasmon differs in each of the antenna layers, and. Consequently, a plurality of wavelength components of light can be detected.

Photodetector having first and second antenna areas with patterns having different cycle intervals

The invention relates to a photocathode having a structure that permits a decrease in the radiant sensitivity at low temperatures is suppressed so that the S/N ratio is improved. In the photocathode, a light absorbing layer is formed on the upper layer of a substrate. An electron emitting layer is formed on the upper layer of the light absorbing layer. A contact layer having a striped-shape is formed on the upper layer of the electron emitting layer. A surface electrode composed of metal is formed on the surface of the contact layer. The interval between bars in the contact layer is adjusted so as to become 0.2 &#x3bc;m or more but 2 &#x3bc;m or less.

A UV sensor () includes a container () in which the upper end opening of a metal side tube () is sealed with a front plate () composed of borosilicate glass as an incident light window and the lower end opening is sealed with a base plate (). The front plate () serving as an incident light window constitutes part of the wall of container () by sealing the upper end opening of the metal side tube (). A pin-type photodiode () is disposed inside the container (). The pin-type photodiode () comprises a photoabsorption layer () formed from InGaN (0&#x3c;x&#x3c;1) between an n-type contact layer () and a p-type contact layer ().

UV sensor

A semiconductor light-receiving device has a substrate including upper, middle and lower regions in its front side. A p-type layer on the lower region has a top surface including a portion on a level with the middle region. An electrode covers at least part of the boundary between the portion of the p-type layer and the middle region. An n-type layer on the p-type layer has a top surface including a portion on a level with the upper region. Another electrode covers at least part of the boundary between the portion of the n-type layer and the upper region.

Semiconductor light-receiving device

A transmission secondary electron emitter is provided which emits secondary electrons generated by the incidence of primary electrons. The transmission secondary electron emitter includes a secondary electron emitting layer which is made of diamond or a material containing diamond as a main component, and of which one surface is the surface of incidence for making the primary electrons incident thereon, and the other surface is the surface of emission for emitting the secondary electrons. Also included is a voltage applying arrangement for applying a predetermined voltage between the surfaces of the incidence and the emission of the secondary electron emitting layer to form an electric field in the secondary electron emitting layer.

Transmitting type secondary electron surface and electron tube

Provided are a photocathode plate capable of stably achieving a high sensitive property, and an electron tube using such a photocathode plate. In a photomultiplier tube, an insulating layeris formed between a semiconductor electron emission layerin a photocathode plateA, and a first electrodeelectrically connected to an electron releasing portion. This insulating layerpermits the photocathode plateA to be cleaned by heat cleaning at a high temperature, in a stage before formation of an active layeron an exposed region of the semiconductor electron emission layerin the electron releasing portion. This makes it feasible to effectively clean the exposed region of the semiconductor electron emission layerin the electron releasing portionand to stabilize the physical properties of the exposed region. In consequence, a higher sensitive property can be stably achieved in the photocathode plateA and in the photomultiplier tubeusing the photocathode plateA.

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Hamamatsu, Japan

Minoru Niigaki