EP2160766A1 - Mesure de puissance de rayonnement absolue - Google Patents

Mesure de puissance de rayonnement absolue

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Publication number
EP2160766A1
EP2160766A1 EP08761717A EP08761717A EP2160766A1 EP 2160766 A1 EP2160766 A1 EP 2160766A1 EP 08761717 A EP08761717 A EP 08761717A EP 08761717 A EP08761717 A EP 08761717A EP 2160766 A1 EP2160766 A1 EP 2160766A1
Authority
EP
European Patent Office
Prior art keywords
detector
radiation
measuring
measuring arrangement
wavelength
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP08761717A
Other languages
German (de)
English (en)
Other versions
EP2160766A4 (fr
Inventor
Erkki Ikonen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Aalto Korkeakoulusaatio sr
Original Assignee
Teknillinen Korkeakoulu
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Teknillinen Korkeakoulu filed Critical Teknillinen Korkeakoulu
Publication of EP2160766A1 publication Critical patent/EP2160766A1/fr
Publication of EP2160766A4 publication Critical patent/EP2160766A4/fr
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0216—Coatings
    • H01L31/02161—Coatings for devices characterised by at least one potential jump barrier or surface barrier
    • H01L31/02162—Coatings for devices characterised by at least one potential jump barrier or surface barrier for filtering or shielding light, e.g. multicolour filters for photodetectors
    • H01L31/02165—Coatings for devices characterised by at least one potential jump barrier or surface barrier for filtering or shielding light, e.g. multicolour filters for photodetectors using interference filters, e.g. multilayer dielectric filters
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0232—Optical elements or arrangements associated with the device
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/02—Details
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/02—Details
    • G01J1/0271—Housings; Attachments or accessories for photometers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/02—Details
    • G01J1/04—Optical or mechanical part supplementary adjustable parts
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/02—Details
    • G01J1/04—Optical or mechanical part supplementary adjustable parts
    • G01J1/0407—Optical elements not provided otherwise, e.g. manifolds, windows, holograms, gratings
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/02—Details
    • G01J1/04—Optical or mechanical part supplementary adjustable parts
    • G01J1/0407—Optical elements not provided otherwise, e.g. manifolds, windows, holograms, gratings
    • G01J1/0411—Optical elements not provided otherwise, e.g. manifolds, windows, holograms, gratings using focussing or collimating elements, i.e. lenses or mirrors; Aberration correction
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/02—Details
    • G01J1/04—Optical or mechanical part supplementary adjustable parts
    • G01J1/0407—Optical elements not provided otherwise, e.g. manifolds, windows, holograms, gratings
    • G01J1/044—Optical elements not provided otherwise, e.g. manifolds, windows, holograms, gratings using shutters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
    • G01J1/4257—Photometry, e.g. photographic exposure meter using electric radiation detectors applied to monitoring the characteristics of a beam, e.g. laser beam, headlamp beam
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0216—Coatings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0232—Optical elements or arrangements associated with the device
    • H01L31/02325—Optical elements or arrangements associated with the device the optical elements not being integrated nor being directly associated with the device

Definitions

  • the invention relates to radiation measurement technique in a general level.
  • the invention relates more specifically to radiation power determination according to the preamble of an independent method claim on measuring method.
  • the inven- tion relates also to detector according to the preamble of an independent detector claim.
  • the invention relates also to photodiode according to the preamble of an independent photodiode claim.
  • the invention relates also to measuring arrangement according to the preamble of an independent measuring arrangement claim.
  • the invention relates also to measuring system according to the preamble of an inde- pendent measuring system claim.
  • cryogenic radiometer appears to be the most accurate of the known devices.
  • Such technique provides a technique to measure optical power within a 100 ppm accu- racy by cooling the measuring device to low temperatures, to the temperatures of liquid helium, i.e. about 4 K.
  • the precision appears to be in a reasonable level for many applications, the liquid helium and the related cooling arrangement makes the measurements expensive while the equipment consumes energy for the cooling of the coolant which is also quite expensive as such.
  • heavy cooling apparatus can also influence on the portability and thus to the applicability of the instrumentation in portable, or almost portable devices.
  • DBR Distributed Bragg Reflector
  • a photo diode utilises pure silicon body, beneath an oxide layer area (considered as a region with a thickness), for the conversion from photon energy to electric energy that occurs mainly internally in the silicon body.
  • the oxide layer can be used as electrode for the photo diode.
  • EQE External Quantum Efficiency
  • the plateaus trap detector structure may improve the EQE
  • separate plates as detectors may be not only expensive as such, but their electrical properties may be different, if the plates are not made of the same batch and/or crystal, the mounting may be sensitive to the mounting errors and accuracy, even to minor deflecting ones, and diffuse reflectance of the radiation from the planar photodiodes may cause an uncertainty component which is difficult to estimate.
  • trap detectors are known to show increasing diffuse reflectance with time.
  • the invention relates to observation, that the measurement accuracy can be increased.
  • the detector with thick oxide layer on pure silicon body (and/or a natural inversion layer) can operate so that the IQE keeps very high within a certain oxide layer thickness range for a wavelength.
  • the invention relates to the improve- ment of the External Quantum Efficiency (also referred as EQE).
  • the product of IQE and EQE as closely to 1 or in per cents to 100 % as possible.
  • Detector according to an embodiment of the invention is characterized in that what has been stated in the characterizing part of an independent claim on photodiode.
  • Measuring method is characterized in that what has been stated in the characterizing part of an independent claim on measuring method.
  • Measuring arrangement is characterized in that what has been stated in the characterizing part of an independent claim on measuring arrangement.
  • Power meter according to an embodiment of the invention is characterized in that what has been stated in the characterizing part of an independent claim on power meter.
  • Photodiode according to an embodiment of the invention is characterized in that what has been stated in the characterizing part of an independent detector claim.
  • Measuring system is characterized in that what has been stated in the characterizing part of an independent system claim.
  • the preamble part to define the technical field of the claim and the characterizing part of a claim in the claims have been formally differentiated from each other by using at least one of the expressions: characterized in that, comprise and/or wherein, with a bolded font where applicable to the subject matter as whole, ac- cording to the way of saying and/or lingual deflection adapted to the context, but without any intention to limit the wholeness of the claim featured with features of technical field and/or the technical matter of the claim in a combination, made for the prosecution in such countries that demand two part claims, and in each claim to be interpreted for the application ownerDs interest
  • the way of marking is not made restricting rather than to improve readability in lingual sense, and to guide the reader to the correct technical field and/or patent classification.
  • radiation power is measured by measuring the current that originates from radiation photons to be converted to electron-hole pairs that constitute said current.
  • the radiation is brought at a Brewster angle to the surface layer, then into the detector body in which the quantum conversion of the photons to electron-hole pairs is to be occurring.
  • the angle of incidence is smaller, for a component of radiation having a wavelength and/or another feature of radiation, than the Brewster angle for a component of said radiation having the wavelength and another feature for radiation corresponding to the Brewster angle.
  • the angle of incidence is larger, for a component of radiation having a wavelength and/or another feature of radiation, than the Brewster angle for a component of said radiation having the wavelength and another feature for radiation corresponding to the Brewster angle.
  • a thin film structure on a substrate as arranged to receive the radiation at the Brewster angle can be used as an electrode for the detector, or as a surface on which further electrodes can be embedded so that the current from the quantum conversion can be measured.
  • the macroscopic beam as such may have internal variations for angles of propagation of certain modes of the beam and thus also to cause a variation in angle of incidence at the Brewster angle at the detector surface so that the direction representing angles from which they arrive to the detector surface may have a narrow distri- bution.
  • the detector surface may have a microstructure so that at least some of said modes and/or components of the radiation beam may appear to experience the angle of the incidence different than exactly the ideal Brewster angle were for an observer experiencing a macroscopic view.
  • the detector can be implemented by a semiconductor detector.
  • the detector can be optionally implemented by a tube comprising a filling, such as gas for instance, so that the tube is arranged to operate as detector.
  • the gas filling can operate as such as an absorber for certain wavelengths of radiation if some of such wavelengths were unwanted for an embodiment to meet the detector material on an inner sur- face of the tube.
  • the gas is in so low pressure that it is regarded as vacuum in practice.
  • the tube can be coated with a layered structure so to enhance the interaction of the introduced radiation in the layered structure and/or filling.
  • the coating is inside the tube, on the wall surface.
  • DinsideD should be understood as the side of a (by inder for example where the symmetry axis were in respect to the wall of a single cylinder, however, without limitation to the mere mentioned example.
  • the detector can comprise a detector arranged as a trap detector, but the detector material arranged to form such a de- tector which has a spherical or a spheroidal cross section.
  • a unite detector surface is mechanically stable, and/or electrically sufficiently uniform.
  • at lest one end comprises a sphere segment shaped detector material.
  • a detector tube comprises mirrors and/or several electrodes arranged to increase the external quantum efficiency yield.
  • the detector layers so form a roll in tube, for instance.
  • the tube can be in practical vacuum, but according to another embodiment the tube can have filling, which is made of gas so that the tube is arranged to be filled at least partly by the gas.
  • the tube comprises walls that allow the pressure of the gas to be used for modifying the optical density of the gas filling.
  • the detector comprising arrangement and/or the system can comprise pressure controlling means arranged to control the pressure (and/or temperature) at least at the surrounding volume where the radiation beam hits the detectorDs surface first time, i.e. where the influence of the
  • EQE has been about to end for the very incident beam part to the detectorDs so- face.
  • the detector can be at least partly coated with a layer filter to prevent an unwanted part of the radiation to get into the detector.
  • the detector can be at least partly coated with a layer structure that is arranged to prevent a wanted part of the radiation to get out of the detector.
  • the structure comprises a grating, mirror, DBR or a combination thereof.
  • the detector, the detector comprising arrangement and/or the system comprise temperature controlling means that means further comprise a Peltier element for controlling the temperature of the detector at the radiation input spot in/on the detector.
  • the temperature controlling means comprises additionally a heating means arranged to control the temperature at the radiation input spot into the detector into a pre-determined value.
  • the detector comprises a cavity, which is arranged for the absorption of the light directed to a surface of said cavity so for trapping the light.
  • the cavity means a volume that is filled at least partly with material that has a different structure and/or composition as the cavity walls.
  • a detector is implemented as it were forming a well into a silicon body so that said well extends into the silicon body so that the radiation beam meets the wall of the well in a Brewster angle at least once, but the specularly forwarded reflected pattern hits the well wall so that the beam would be approximating a spiral- like conical path into the deepness of the well.
  • the well can be made into a silicon crystal, but more advantageously onto a flexible substrate.
  • the ends of such a well can comprise a mirror and/or a suitable detector structure according to an embodiment of the invention.
  • a cavity according to an embodi- ment of the invention comprises at least a part that is arranged to operate as a DBR-structure for absorption of the radiation directed to a surface of said cavity.
  • the cavity is constituted by the silicon substrate body in which the radiation is arranged to be converted to the electron- hole pairs.
  • the filling of the cavity is a liquid substance filling at least partly the cavity.
  • the cavity can comprise multiple solid parts arranged to absorb radiation as the detector and so to operate as co-detectors.
  • the DBR-structure comprises a grating.
  • the DBR-structure is arranged to operate as diffraction optics, advantageously to keep the wanted part of the radiation to be measured in the detector.
  • the DBR-structure at least one of such is arranged on a substrate body, as a layer that comprises a number of sublayers.
  • the layer number is larger than 2.
  • the number of layers is larger than 10.
  • the number of layers is lar- ger than 20.
  • the number of layers is less than 100.
  • the number of layers is less than 300.
  • the layers are arranged to bend the radiation path towards the detectorDs ⁇ uch part in the body that is used in the conversion with the IQE.
  • the structure can be used in a reflector, with a curvature, made from silicon in order to increase the product of IQE and EQE for the reflector, so facilitating such a reflector to be used as a detector part in the conversion of radiation energy to electrical energy according to an embodiment of the invention.
  • the sub-layer structure can be used for to set the reflection properties with the sub-layer number for improving the product of IQE and EQE.
  • the sub-layer number is larger than 2.
  • the number of sub-layers is larger than 10.
  • the number of sub-layers is larger than 20.
  • the number of sub- layers is less than 100.
  • the number of layers is less than 300.
  • two DBR-structures are arranged on a substrate, for improvement of the product of IQE and EQE, according to one variant into a stack so that the stack comprises at least one layer in which the quantum conversion is aimed to happen, at least partly, but according to another variant the DBR structures can be different and they are so situated that they are not directly on each other in contact, but rather by a medium layer.
  • a first DBR structure with a first type but also a second DBR structure with a second type.
  • the first and/or second types of the DBR-structures are manufactured into the detector and can be arranged to be selected from a layered structure in an oxide layer, a layered structure on an oxide layer, a layered structure in an anti reflection coating layer, a layered structure on a reflection coating layer, a layered structure on a substrate body of the detector material, a layered structure between an antireflection coating on a substrate body of the detector material, a grating in oxide layer, another antireflection coating layer, a grating on a substrate body of the detector material, a grating between a substrate body of the detector material and an oxide layer, a mirroring surface at the edge of a detector body, or a part thereof arranged to direct oxide layer wave guide modes into the detector body, an anomaly in the substrate body, an anomaly in the oxide layer, and a cavity of the oxide layer to form a surface to direct photon radiation into the silicon body.
  • a first optical coefficient of refraction for a DBR-structure comprising the low reflectance material is selectable in range 1.0001 - 5.
  • a second optical coefficient of refraction for a DBR-structure comprising the high reflectance material is selectable in range 1.0001- 5, but higher or equal than said first optical coefficient, for the wave length in wavelength range in question.
  • the DBR structure is at least one of the following: said first DBR-structure and said second DBR-structure.
  • a DBR structure of a grating type is used for reflecting photon radiation back to the path leading to the detector body.
  • the cavity comprises at least a part that is arranged to operate as a Rayleigh horn type trap arranged to trap radiation for absorption of the radiation directed to a surface of said cavity.
  • the cavity comprises at least a part that is arranged to operate as a focusing mirror to focus radiation on to the radiation sensitive area of the detector or another part implemented by another cavity comprising the detector.
  • the mirror is implemented by a paraboloidal mirror or spherical mirror.
  • the detector is on a surface facing to the mirror and/or a cavity surface.
  • the detector material is arranged to be on the surface that has a shape of the mirror and/or said cavity surface, advantageously arranged for a focusing geometry, but according to an optional embodiment in a non-focussing geometry which can be at least a planar geometry or in suitable part a diverging geometry so to be arranged to deal with higher radiation fluxes, for embodiments and thus division of radiation power on a larger area than on that of the mirror.
  • a non-focussing geometry which can be at least a planar geometry or in suitable part a diverging geometry so to be arranged to deal with higher radiation fluxes, for embodiments and thus division of radiation power on a larger area than on that of the mirror.
  • the geometry is diverging
  • the cavity comprises at least on one surface an antireflection coating layer arranged to interact with the radiation to be absorbed, but arranged so that the layer actually guides photons back into the de- tector body for the conversion .
  • the detector comprises at least one film layer, but according to another embodiment many film layers.
  • the layer comprises Si, Ga, As, P, In, Sn, Pb, C, Ge or a combination of the just mentioned.
  • the detector according to an embodiment of the invention can be utilised in a layer thickness metering device.
  • Fig. 1 illustrates an embodiment of the invention
  • Fig. 2 illustrates a detail in an embodiment of the invention
  • Fig. 3 illustrates a detector surface structure according to an embodiment of the invention
  • Fig. 4 illustrate an adjustable detector surface structure according to an em- bodiment of the invention
  • Fig. 5 illustrates a detector surface structure according to an embodiment of the invention
  • Fig. 6 illustrates a detector surface structure according to an embodiment of the invention to provide a multilayer structure
  • Fig. 7 illustrates a detector system according to an embodiment of the invention
  • Fig. 8 illustrates a measurement system according to an embodiment of the invention
  • Fig. 9 illustrates a measurement method according to an embodiment of the invention
  • Fig. 1 OA illustrates reflection as a function of the angle of incidence for a 500 nm photon radiation reflected from a Si diode surface with various indicated oxide layer thicknesses
  • Fig. 10B illustrates reflection as a function of the angle of incidence for an 800 nm photon radiation reflected from a Si diode surface with various indicated oxide layer thicknesses
  • Fig. 10C demonstrates reflection as a function of the angle of incidence for photon radiation with the indicated wavelengths from Si diode surface with various indicated oxide layer thicknesses in range of 2900-2916 nm, and
  • Fig. 11 illustrates photon radiation passage in a Si diode.
  • the power of a photon radiation can be measured as measuring electric current in a suitable system, provided that the frequency f (or the wavelength) is known.
  • a current is provided, as- suming 100% EQE, according to (2):
  • the tyflle presents the yield after each various loss mechanisms, internal (IQE) and/or external (EQE) by the number of k that have a significance to the radiation power before the radiation is brought into the material that is supposed to generate the electron-hole pairs.
  • IQE internal
  • EQE external
  • the incident radiation can get absorbed into the photo detector, especially when the detector is made of silicon, so that at least 99 % of the p-polahzed photons are absorbed while arriving to the photo detector at the Brewster angle.
  • the oxide layer thickness has a tolerance of essentially smaller than 10 nm, advantageously smaller than 5 nm, but according to an optional embodiment smaller than 3 nm.
  • a tolerance applies for an area of an oxide layer having a thickness, which area can be a unite area that is smaller than 1 ⁇ m 2 , advantageously smaller than 1 mm 2 , more advantageously smaller than 1 cm 2 but preferably larger than at least ten per cents of the area of a single detector.
  • the tolerance applies to the surface in perpendicular direction to the surface with defects having a diameter in parallel direction of the surface less than a wave length of the radiation, but more advantageously less than 1/10 the wavelength.
  • a tolerance applies for an area that is a non-connected area as such to form detector parts.
  • the radiation used in the power measurement can be a fixed wavelength radiation.
  • common three wavelengths 790 nm, 633 and 488 cf. the wave lengths indicated in Fig 10C
  • a single structure comprising an ox- ide layer of 2908 nm on silicon.
  • Other suitable wavelengths are 529 nm, 576 and 703, or other fixed or non fixed radiation source wavelength, as a skilled man in the art can realize from the embodiments of the invention when read and understood the text, as well as the Examples .
  • the reflectance depends on the oxide layer thickness periodically for a first wave length with a first period, and for a sec- ond wave length with a second period, overlapping reflectance minima occurrences can form a resonance for the plurality of said wavelengths.
  • the oxide layer thickness can be utilised that corresponds occurrences of resonances of minimum reflectance with a fixed oxide layer thickness.
  • the radia- tion can be provided with suitable radiation source.
  • the antireflection coating has a very low opacity other than that of silicon dioxide in an optional embodiment of the invention.
  • the oxide layer thickness can be selected according to the oxide layer as above mentioned in respect to the desired wavelength.
  • a reference to example 1 is made.
  • at least one of the radiation sources is replaced by a versatile source to provide several wavelengths, but is used as a fixed radiation source with the corresponding wavelength.
  • the availability of ad- justable radiation sources may limit the selection of the thickness of the oxide layer, for the absolute radiation power measurement.
  • the approximate fraction of 0.1 % of the photons, as specularly and/or diffusively reflected, can be directed to a photo detector, i.e. photo diode for instance, made of suitable material.
  • the detector comprises a pure silicon body coated with a uniform oxide layer for example.
  • the directing of the incoming radiation can be made by means that are arranged to direct the radiation into the detector.
  • Such means can comprise collimating means implemented by lenses and/or pinholes.
  • One ensemble of embodiments comprise a cavity comprising same material on the cavity walls, as the above mentioned photo-detector is made of, but also in addition or optionally arranged to utilise a mirror that has a form of sphere segment and/or a shape of a paraboloid arranged to direct the radiation to the detector.
  • the mirror is made of photo detector material with suitable structure implementation so actually operating actually as a very poor re- fleeting mirror.
  • a spherical mirror is advantageous because the angular distribution of the diffusively reflected radiation and the reflectance provide means to determine the portion of the radiation that escapes from the input orifice through which the incident radiation is inputted, before the very first reflection in the detector, on the spot hitting the detector, and also means to provide an estimate for the loss in the reflection.
  • a paraboloid mirror can be used, so that the diffusively reflected light can be directed by the paraboloid mirror to a uni-directional path and so to measure the radiation with detectors situated in the plane of the element which had the first reflection of the inputted radiation.
  • Such a measurement yields sufficient information of the diffuse reflection of the photodiode, especially on the absolute value of the angular distribution.
  • An advan- tage of paraboloidal mirror can be utilised to achieve a well defined direction of the collected diffuse and thus back-reflected radiation towards the detector surface, so that the divergence of the back-reflected angle can be minimized, by using the col- limation properties of such a paraboloidal mirror, and thus so to have the angle in which the radiation meets the detector surface as well defined direction for the ra- diation, to direct the path of radiation from the surrounding volume of the detector into the detector by the mirror.
  • a solid state detector can be implemented by utilising a layered structure that comprises at least one layer in a plurality of layers, for which at least one layer is arranged to comprise oxide so that such wave guide modes that connect to the oxide layer due to the scattering are reflected back before their entry into the detector edge.
  • the reflector has been implemented by DBR.
  • the layered structure can be a mirror arranged to the edge of the oxide layer with a suitable tilt and/or curvature so to reflect the wave guide modes towards the detector body.
  • the reflector can be implemented by a periodic structure patterned in or on the oxide layer and/or the substrate.
  • Such a diffraction grating can reflect the wave guide modes back into the detector material, advantageously into the silicon body.
  • the wave guide modes are absorbed at the oxide layer edge into the surrounding detector body material.
  • the oxide layer can be embedded into the silicon substrate constituting the detector body.
  • the detector comprises a cavity in a silicon piece with the silicon oxide layer having thickness of antireflection coating for a photon radia- tion.
  • a periodic structure is arranged to operate for a wave length, but according to another embodiment to operate for at least one wave length, but also for more wavelengths.
  • the detector according to an embodiment of the invention as embodied by a photodiode for instance can be oper- ated in a radiometer in temperatures that are near the temperature of liquid (I) ni- trogen N(I), which is easy to handle in technical sense, the costs of the N(I)- coolant are lower and the cryogenic equipments consume less power for the cooling. Thus, the maintenance costs are lower and also the mechanical size can be smaller.
  • the radiometer can absorb the incoming light in a spot and the surrounding, so that the diffuse reflections can be controlled so contributing to a simple structure for the device, if compared to the technique in which several specular reflections were to be controlled.
  • a radiometer according to an em- bodiment can be manufactured for utilisation in several wave length ranges, provided that the thickness of the oxide layer on the silicon, in the corresponding embodiment, can be controlled within a tolerance of 10 nm, advantageously within a tolerance of 5 nm and even more preferably 2 nm or better.
  • a radiation source that has a laser can be used as the light source that has a tunable wavelength.
  • other radiation sources can be used, also fixed ones in one variant of an embodiment.
  • each desired wavelength to be used in the measurement can have each an own dedicated radiometer for the wavelength correspond- ing wavelength range so to comprise a system of radiometers.
  • a detector operable as a photodiode that comprises a thin film coating is arranged to improve the EQE of the photodiode for radiation coming into said thin film in a Brewster angle.
  • the detector structure in a photo-diode to be used in the detector has an oxide film on a substrate.
  • said substrate is silicon substrate.
  • the oxide is a silicon oxide.
  • said oxide comprises another substance in the oxide structure less than 10 20 atoms per mole of silicon atoms.
  • the detector comprises at least one further layer.
  • a detector according to an embodiment of the invention is used in a system according to an embodiment of the invention.
  • the system comprises also a radiation source for the radiation.
  • the radiation is monochromatic radiation.
  • the radiation is coherent radiation.
  • the radiation comprises at least two radiation components each having a predefined wave length.
  • the radiation comprises radiation that has components of less than a dozen of wavelengths from which at least one has a monochromatic and/or coherent feature.
  • the detector has been implemented by a semiconductor detector.
  • the detector has been implemented by a tube comprising a gas filling, so that the tube is arranged to operate as detector.
  • the detector comprises a cavity, which is arranged with detector material walls and detector structure arranged for the absorption of the light directed to a surface of said cavity.
  • the cavity comprises at least a part that is arranged to operate as a Rayleigh horn, or another kind of a trap, for absorption of the radiation directed to a surface of said cavity, to be used as a part of a trap detector according to an embodiment of the invention.
  • the cavity comprises at least a part that is arranged to operate as a DBR-structure for improve the IQE related absorption of the radiation directed to a surface of said cavity.
  • the cavity comprises at least a part that is arranged to operate as a well or as a Rayleigh horn for absorption of the radiation directed to a surface of said cavity.
  • the cavity comprises at least a part that is arranged to operate as a focusing mirror to focus radiation on to the radiation sensitive area of the detector or another part implemented by another cavity comprising the detector.
  • the mirror is implemented by a paraboloidal mirror or spherical mirror.
  • the incident beam meets the detector surface in the Brewster angle at the first time at the hit spot, in a plateaus part of the detector.
  • the detector comprises another part that is arranged in form of a spherical mirror to surround concentrically the hit spot. That another part comprises same detector materials arranged same way as the plateaus part. So, said another part actually operates as a poorly operating mirror, but very efficient de- tector, utilising the advantage of the optical geometry to reflect the non-absorbed minor part back to the plate having the hit spot.
  • the detector is arranged on a substrate body by a surface that is facing to the mirror and/or a cavity surface.
  • the mirror comprises bulbous layers arranged to absorb as many orders as possible of the reflected radiation between the layers of the bulbous structure.
  • at least one of the mirrors comprises a coating capable of act as the detector.
  • the detector material is arranged to be on the surface that has a shape of the mirror and/or said cavity surface in a focusing geometry, but according to an optional embodiment in a non-focussing geometry which can be at least a planar geometry or in suitable part a diverging geometry arranged to deal with higher radiation fluxes for division on a larger area than on that of the mirror.
  • the cavity comprises at least on one surface a silicon layer arranged to interact with the radiation to be absorbed. According to an embodiment of the invention the cavity comprises at least on one surface an antireflection coating layer arranged to interact with the radiation to be absorbed. According to an embodiment of the invention the cavity comprises at least on one surface an antireflection coating layer arranged to interact with the radiation to be absorbed.
  • the detector comprises at least one film layer. According to an embodiment the detector has at least two locations to form a diversified detector.
  • the layer to be used in the detector comprises at least Si and an oxide layer thereof.
  • the detector comprises alternatively or in addition to pure silicon and its oxide Ga, As, P, In, Sn, Pb, C, Ge or a combination of the mentioned.
  • Fig 1 illustrates an example according to an embodiment of the invention.
  • the radiation source 101 radiates radiation 102.
  • the radiation is coherent and/or monochromatic photon radiation.
  • the radiation is laser radiation.
  • the radiation is in optical range of visible light.
  • the radiation comprises a component from UV- and/or IR-range.
  • the radiation can be polarized radiation, for instance such as in a p-polarized laser beam.
  • the Brewster angled vacuum window 112 is arranged to pass the incoming radiation 102 into the detector volume 113 via the inlet part 111.
  • the window 112 is provided with preferably known and high efficiency.
  • Inlet part 111 comprises advantageously a valve 117 further comprising a control means 109 arranged to control the shutter means 110 so that the entrance of the radiation to the further parts can be stopped and/or prevented.
  • the shutter means can be implemented in an embodiment by a macroscopic means, but according to an embodiment of the invention the shutter 109 can be implemented by a liquid crystal means and/or mems-related micro lamels or rolls for the photon radiation related aspects.
  • At least one of the parts 111 and 113 comprises optionally or in addition advantageously also a sealing valve, which can be located for instance with the valve 117 to provide a joint point.
  • a sealing valve can be used when the parts 111 and 113 are arranged to be mutually detachable from each other, so to detach the part 113 from the part 111 without breaking the atmosphere in the part 113 and the pressure P, as in a practical vac- uum, can remain, even if the parts 111 and 113 were separated. That is an advantage when the part 113 is used in more than one location, or it is used to replace another suitable detector structure.
  • the detector 108 is a polarization detector arranged to detect the radiation after its entry into the part 111 after back-reflection from 107.
  • the detector can be arranged to detect s-polahzed light, and thus can be used to estimate back reflectance from an optical path leading to said detector, and so to estimate radiation that escapes from the detector in a geometry apparent from the figure.
  • the radiation beam 103 is of the same radiation origin as the radiation 102, but a different reference numeral is used to discriminate the parts of the (momentary) radiation path.
  • the radiation path comprises at least one of the following path parts 102, 103, 104, 105, 106 so depending on the position of the radiation source 101.
  • the point or hit spot of radiation beam to hit the detector surface is marked by item 104.
  • a reflection from the detector surface 118 (Fig 1 ) is indicated by the ray 105, which hit the mirror surface 107 at the spot of the arrow spike.
  • the items 106 illustrate some directions of diffuse reflection.
  • the angle of ray 103 is not exactly at the Brewster angle, but illustrated so only to indicate the existence of the ray 105 on the corresponding path to the shown direction.
  • the reflectance can be 99.5 % or better and the point is close to the position of specular reflection from 118.
  • the mirror 107 can be implemented by a surface having a reflectance that is equal or higher than 90%, provided that mirror does not have detector material and/or structure according to an embodiment.
  • the mirror 107 is made as to operate as detector with the structure and composition of a detector according to a suitable embodiment.
  • Fig 1 shows the operating temperature T in which the detector is supposed to be working according to an embodiment of the invention.
  • the pressure P is an ambient pressure.
  • the T is equal or more than 10 K.
  • the T is equal or more than 50 K.
  • the T is equal or more than 100 K.
  • the T is equal or less than 175 K.
  • the T is equal or less than 220 K
  • the T equals to boiling point of liquefied nitrogen at the corresponding pressure.
  • the detector volume 113 is kept in a vacuum, but so that the surrounding structures are kept in T by a coolant cooled to the said temperature.
  • vacuum means in order to evacuate the detector surrounding volume or a part thereof, vacuum means can be used to make and/or to maintain the vacuum, i.e. conditions in which there is less gaseous medium or media phase material present in the volume than in the ambient conditions.
  • the pressure P is less than about 0.1 Atm.
  • the pressure P is less than 0.01 Atm.
  • the pressure P is less than 0.001 Atm.
  • the pressure is higher than the pressure in intermolecular space in gas.
  • the radiation beam 103 is collimated by collimating means 114.
  • the colli- mating means 114 comprises a disk-like piece that has the part 116 so defining an opening and/or an orifice for the radiation to be collimated.
  • the collimating means can be embodied by tube-like means comprising the part 115 arranged to collimate the radiation beam 103.
  • the entrance aperture for the radiation 103 can be used for the collimation.
  • lenses and/or conventional mirrors can be used for collimating the radiation beam whose power is about to be meas- ured, optionally or in addition to the means 114 and/or means 116, to be used for arranging the beam to meet the detector in Brewster angle.
  • the mirror 107 can be embodied as a spherical reflector arranged to reflect the diffuse radiation to a spot on a detector for forming therein electron-hole pairs and thus contributing to the electrical current.
  • the spot 104 is the center of the spherical part 107.
  • the reflector can be optionally embodied by a paraboloidal surface.
  • the mirror has an opening for the entrance of the beam 103. According to an embodiment the opening is arranged so that the open- ing has a well known area with high accuracy and operates as a collimator part.
  • the spherical part can comprise planar mirrors and/or detectors in advantageous directions to increase the yield of the product of IQE and EQE towards 1.
  • the EQE is maximized.
  • the loss of the radiation in a reflection event is minimized optionally or in addition to EQE maximization.
  • the reflector 107 can comprise an area or region that is switchable to at least one of the states connected and non-connected as arranged to operate as a detector as the part 118 or to guide radiation at least in some extent to the detector part 118.
  • an area or region can be arranged in a forward direction of the radiation in its path after a first reflection, according to an embodiment also repeatedly to catch the specular reflections.
  • the reflector 107 can be made in such an embodiment cheaper than by making the whole 107 from detector material. So, the reflec- tor 107 can be manufactured by machining for instance, casting and coating or by a work.
  • the reflector can be arranged to have a coating with a detector material for using it as a detector and the related layers and/or DBR structures.
  • the 107 can be provided with a mirror surface and in an embodiment variant with non -uniformity locations embodied as detectors or as holes or other formations guiding the radiation to a detector.
  • the mirror 107 has, alternatively to an embodiment in which the 107 has mirror surface in conventional meaning, very large absorbance, preferably in the embodiment even the same as or as closely as practically possible as the absorbance of the detector part 118, so actually deflect- ing from the operation of an ordinary mirror, and so actually facilitating to convert to the mirror 107 incoming radiation photon energy according to its quantum efficiency to electric current so facilitating the yield increase also from that part of the radiation that could escape by several mechanisms from the 118 at the spot 104.
  • the mirror 107 so embodied can act as a secondary detector or a part of the detector, depending on the desired geometry and mirror type for the measurement.
  • the secondary detector 107 is used in the embodiment in question as a separately coupled or in parallel coupled with the detector 118.
  • Fig 4 gives further examples on such embodiments.
  • the Fig 1 embodies a cross section from such an embodiment that util- izes a spherical mirror 107
  • the cross section in the figure also demonstrates, that the mirror 107 could comprise a cylinder part formed curvature for the mirror, so that said cylinder has the axis at the point 104 extending parallel with the normal of the page at the point 104.
  • the mirror 107 is formed by such a cylinder, and the primary detector 118 and/or the input system for the collimated light is/are slightly tilted so that the part of the radiation that potentially escapes from the spot 104 from the first reflection is directed to the cylindrical mirror surface at a second point, on the mirror, but if there were still some even lesser part of the radiation to escape the mirror 107 because of reflection or scattering at said second point, the tilt of detector 118 is arranged so that the ra- diation were about as to experience an endless spiral like path in the maze until extinction in the mirroring occurrences has emptied the radiation from its capability to further conversions to electric current.
  • the mirror 107 as actually embodied as detector comprises a cylindrical form.
  • the detector part/mirror 107 has a form of ice-cream cone.
  • the detector part 118 can be designed to have a non-planar form for having the surface curvature of parabolic mirrors, used as such in telescopes, to focus the diffusively reflected and/or scattered rays better on to a certain point on the mirror 107 surface.
  • the mirror 107 has also at least one similar kind of part that is arranged as the detector 118 in a non-planar embodiment.
  • the cylinder has spheroidally or spherically curved ends so to keep the radiation reflected in multiple times as long as possible for a high yield EQE.
  • the mirror 107 can have plane like tilted or pivoted plates in suitable part as arranged to guide and/or increase the EQE of the detector.
  • the collimator means 114 are arranged so that some radiation after the collimation hit the mirror/detector 107 at the back side around the entrance opening and thus compensate a certain portion of the radiation that supposed to hit the mirror at opening location, so that the portion is defined by the geometry of the opening and the collimating means.
  • the mirror/detector comprises detector material arranged to convert the radiation photons to electron-hole pairs, but also outside side of the mirror/detector, supposing that the inside is the side of the location of the spot 104.
  • the outside side is considered to be the side that is opposite side of the mirror to the detector in an embodiment implemented with a mirror as the part 107.
  • said annular kind of a region is divided into parts, the current from each part can be measured and thus such divided parts can be used to generate a signal to control and concentrate the radiation beam into a desired position for entrance to the volume of detector, the volume defined by the mirror 107.
  • the mirror 107 comprises a similar coating as the detectorDs 118 surface, but is not limited to the mere similarityor equality.
  • the mirror part 107 and the detector part 118 can be connected together or separated so collecting the electric current jointly or separately, as demonstrated with the Fig 4.
  • the detector surface 118 and the mirror 107 surface area that is used as detector can be arranged to be connectable as illustrated in Fig 4 by the dashed line 402 to demonstrate a detector structure 400 according to an embodiment of the invention.
  • the current and/or a related quantity derivable from the current formed by the item 118 can be read by the interface 401 , which can further push the signal for signal processing and/or storing for the data and the related measurement data comprising the condition related data, as temperature, pressure, properties and/or features of the radiation.
  • the interface 401 operation can be controlled, which is indicated by the arrow directing towards the 401.
  • the interface can be used for the controlling of the connection 402.
  • the detector part 118 is arranged to be adjustable.
  • the adjusting is implemented mechanically, but according to another embodiment electrically.
  • the adjusting can be implemented hydraulically.
  • the detector is arranged pivotable around an axis, advantageously near the point 104, so avoiding potential vibrations of the detector and thus enhance the stability.
  • the 107 and 113 contain pluggable escape holes for the specular reflection.
  • the adjusting is arranged to optimize the detec- tor part position in respect for the Brewster angle as the angle of incidence for the radiation beam 103 to be measured.
  • the adjusting is made by electro-mechanical means, so comprising electrical and/or mechanical means.
  • the adjusting is made in a course of an optimization algorithm arranged to have maxi- mum current into an outer circuit as an indicator of the Brewster angle occurrence.
  • the optimization is made for minimum specular reflectance and/or the relating photocurrent.
  • said minimization is made simultaneously with said maximization, at least in some part having a phase which has overlapping there between, but ac- cording to an embodiment of the invention said minimization and said maximization are made independently on each other, for a part of a detector for instance.
  • said minimization and said maximization are made in a serial way with a first number of minimizations and a second number of maximizations in a sequence comprising respective sub sequences.
  • the sub-sequences are interlaced, at least partly.
  • the whole part 113 is arranged to be pivotable.
  • the part 111 is arranged to be pivotable with the part 113.
  • the part 111 can be locked with 113 for the pivoting.
  • the part 113 is arranged to be pivotable in respect to the part 111 at the joint point.
  • the joint point is implemented by a flexible joint.
  • the joint is made at the location of the part 117.
  • the pivoting as such is not limited only to mere horizontal or to mere vertical plane of such respective embodiments.
  • an adjusting / a certain optimization is made in a closed-loop principle, to adjust by a number of successive steps back and/or another number of successive steps forth in order to converge to meet the Brewster angle.
  • the steps can be implemented by defining the error still present to the desired angle until a predefined tolerance is met.
  • the implementation of the adjustment can comprise at its simplest form a scale for angles in the appropriate range and an adjustment knob with an influence on to the axis to vary the tilt of the detector for selecting the angle, as demonstrated in Fig 1 by the bending arrows at right from the 118.
  • the axis can be arranged to have a gear to have the range for suitably enhanced control accuracy.
  • Such an adjustment can be optionally or in suitable part additionally implemented with an electric motor combined to a mechanism to pivot the detectors tilt.
  • the adjustment is arranged by a stepper motor with a pitch between the positions, say for a non-limiting example with an increase/decrease step of 0.1 degrees or even less.
  • the tilting and/or pivoting of the axis and the tilt is controlled by a fluid pressure of a fluid bar having a first height at first angle and a second height at second angle of the detector tilt.
  • a fluid pressure of a fluid bar having a first height at first angle and a second height at second angle of the detector tilt.
  • Fig 2 illustrates a detail of detector that is embodied as a hexagonal photodiode as a detector 118 to show an example of a single photo diode with a substrate 201 , according to an embodiment of the invention.
  • the shape is not limited only to hex- agonal, nor is the number of photodiodes on the substrate 201 although just one is illustrated for clarity reasons.
  • Each of such photodiodes can be arranged for operation with a feature of radiation of its own.
  • at least one photodiode can be arranged to operate with multiple wavelengths. For instance, so that radiation wavelengths 488 nm, 633 nm, 790 nm, can be used with a single oxide layer having a thickness of 2908 nm on the silicon substrate.
  • the wave guide modes are reflected back before they hit the photodiode edge in an embodiment of the invention that utilises reflectors in the detector structure optionally or in addition to the curved mirror of 107.
  • the reflector can be arranged by a periodical pattern made in/on an oxide layer of the silicon substrate and/or in the silicon substrate itself.
  • Such a formation can be used as a Distributed Bragg Reflector, DBR for different wave lengths.
  • DBR is used in the photodi- ode.
  • the DBR has a first geometry 202 arranged to operate in the purpose.
  • the DBR has a second geometry 203 to operate in the purpose. According to an embodiment of the invention both can be used.
  • the arcs 203 in the figure can have a same centre of symmetry, but is not limited only there to.
  • the arcs illustrate to define a region in/on the detector that comprises a DBR-structure that is arranged to prevent and/or return photons back to the detector body.
  • DBR digital versatile disc
  • the arcs can comprise conical mirror structures or gratings that are arranged to keep the photons in the detector body.
  • the photo diode comprises at least a first geometry comprising DBR and/or a second geometry comprising DBR.
  • the photodiode 118 is designed for the purpose of the power measurement application so that 85 % of the Gaussian beam intensity fall to the area indicated by the dashed line 204, and 99,95 % of the Gaussian beam intensity fall to the area indicated by the dashed line 205, respectively representing values with two and four standard deviations.
  • Fig 3 illustrates a detector structure 300 according to an embodiment of the inven- tion.
  • the detector body material 107 and/or 118 is arranged to be under a layer
  • the layer 301 which can be implemented by a simple layer of antireflection coating.
  • the layer 301 can be an oxide layer in one embodiment, but in another embodiment it can be a metal coating layer. According to an embodiment of the invention the layer can be metal oxide layer. According to an embodiment of the invention the layer has a nano-crystalline structure. According to an embodiment of the inven- tion the layer comprises a halogen and/or a metal.
  • Fig 5 illustrates a detector structure 500 that comprises an oxide layer 501 and an intermediate layer 502.
  • the layer 502 comprises at least partly structures of DBR.
  • the layers can comprise structure and/or composition of a layer according to a layer 301 , 202, 203, 210, 211 , but is not limited only thereto or a certain combination of them.
  • Such structures can comprise grating, for instance.
  • the layer 502 drawn onto whole substrate may be not limited only that way, the part 501 and 118 and/or 107 can be in a connection, if not directly, as demonstrated in Fig 4.
  • the layer 502 is made controllable by the interface 401 to provide the functionality illustrated in Fig 4.
  • the layer 502 can implement the connection 402 of Fig 4 so that the layer 501 correspond the layer 107.
  • the layers 501 and 118 are not necessarily stacked on top of each other, i.e. the layer 502, 402 can comprise actually a semiconductor switch and/or the related wiring to the controlling in- terface and/or to couple the detector parts 107 and 118.
  • Fig 6 illustrates a detector structure 600 according to an embodiment of the invention that comprises several layers 601 , 602, 603 on the substrate 118.
  • the layers can comprise structure and/or composition of a layer according to a layer 301 , 202, 203, 210, 211 , but is not limited only thereto or a certain combination of them.
  • the layer 601 and/or 602 comprises an oxide layer and or a DBR layer.
  • a DBR layer can be arranged at least by one of the following items 202, 203, 210, 211 , as demonstrated in Fig 11.
  • the layer 603 comprises a transparent layer arranged in bulbous way to provide the mirror structure in which there are several mirrors 107.
  • the multilayer techniques can be used in for instance for the mirror 107, especially in embodiments in which the part 107 comprises detector body of silicon and a layer- structure on the detector body.
  • the part 107 comprises detector body of silicon and a layer- structure on the detector body.
  • at least one of the layers in Fig 6 is arranged in a bulbous way to comprise pure silicon arranged to act as a detector.
  • the inner (curvature centre side) side of the mirror 107 (see fig 1 ) is made and/or comprises a silicon layer of pure silicon arranged as an oxide free detector body at the very surface.
  • at least one of the other layers, in contact with said pure silicon layer forms an electrode for an outer circuit for photocurrent measurement.
  • Fig 7 illustrates a combined detector structure 700, in which there is a plurality of detectors, each having at least one detector having a detector structure, which detectors 200, 300, 400, 500, 600 are according to an embodiment of the invention so that each detector is comprising at least one detector with a detector structure (301 , 118, 107) that is at least partly same as the detector 100 according to an embodiment of the invention.
  • at least one of said detectors comprises a combination of at least two of detectors according to an embodiment with appropriate structures.
  • at least one of the structures comprises the structure 113 disclosed in Fig 1.
  • At least one of said detector structures is arranged to fit to a part 111 in Fig 1.
  • each of the detector structures in Fig 7 have fixed geometry for a certain fixed wavelength of radiation and thus a suitable thickness of the oxide layer 301 on the detector body 118, 107.
  • at least one of the detector structures is adjustable for adjusting the angle of the incidence.
  • the combined structure is arranged to have a replaceable detector structure to change one detector structure to another.
  • the replacement is im- plemented by a translator to change said detectors.
  • the detector structure 700 parts can be embodied in suitable part into a detector. According to an embodiment of the invention such a detector can be used in an arrangement to implement a method according to an embodiment of the invention, or in a device for the same.
  • Fig 8 illustrates a measurement system 800 according to an embodiment of the invention.
  • the system 800 comprises at least a detector structure 700 according to an embodiment of the invention.
  • the system 800 comprises the cryogenic arrangement 801 arranged to cool at least one detector of the detector structure 700 to its own operation temperature.
  • the system 800 comprises a photon source 101 arranged to provide the radiation whose radiation is to be measured.
  • the system 800 comprises vacuum pump 802 and the maintenance apparatus and related systems.
  • the system 800 comprises infrastructure providing apparatus 803 so providing the necessary amplifiers, interfaces and/or communi- cation lines as well as memory and processors to be used in the measurement data collection and/or controlling the measurements with the system 800.
  • the system 800 parts can be embodied in suitable part into a device.
  • the device is a portable device.
  • the de- vice is a solidly mountable device.
  • Fig 9 illustrates a method 900 according to an embodiment of the invention to be used for the absolute measurement of the power of radiation.
  • the quantum efficiency IQE and/or EQE can be measured and/or so to determine the ratio according to which the detector structure is capable to convert photons to electron-hole pairs, and/or estimating the EQE.
  • the phases are not necessary for each detector type for every measurement, provided that the detector structure (100, 113) of the type provides certain repeatability for the conversion ratio in set conditions.
  • the ratio, the quantum efficiency IQE and/or EQE can be determined also for several condi- tions of pressure and/or temperature conditions, as well as for other features of the radiation.
  • magnetic field can be used in the radiation wavelength modification for Zeeman-effect related modes of the radiation.
  • the method can comprise during the directing at least partly, a phase in which the radiation source is stabilized in radiation power.
  • the measuring method comprises a phase of determining a momentary power of said radiation, which can according to another embodiment comprise a phase of averaging of the measured quantity or a derivable quantity of such quantity measured.
  • the average can be arithmetic, geometric, harmonic, said average made according to as a gliding average or as an average of fixed interval during the data sampling or a weighted average.
  • the average can be taken over a wavelength range, power range, a time range or a combination of the mentioned as weighted for the result desired and/or the measurement condition details.
  • the incoming angle in which the radiation is introduced to the detector and can be defined with respect to the normal of the surface on the film layer is larger than Brewster angle of incoming radiation, but however so that it appears to be so because of the special curvature or another structure on the detector surface in an embodiment, because of the view point or a surface fine structure. Similar way, the incoming angle can appear as smaller than the Brewster angle, depending on the surface structure itself at the very point of the incoming radiation to hit the surface. Inside the radiation beam there might be also some minor divergence present between the modes of the radiation that has their path partly cross-wise the beam at the path.
  • the incoming radiation finally is arranged to come into the detector in the Brewster angle to meet the absorption and the related quantum efficiency apparent in the spoken geometry yielding an illustration of the deviating angle from the precise.
  • the radiation is directed in the phase of directing to the Brewster angle so that the radiation beam meets the detector structure in the Brewster angle and so facilitates the highest available absorption into the detector structure.
  • the measurement method implementation is not limited to any particular exemplified order of execution as such, but in suitable part method phases can overlap or they can be practiced in a different order, as in cyclic way embodied embodiments for example.
  • the measurement equipment can be allowed to stabilize before the exposing phase in the measurement.
  • the detector can be exposed to the radiation, for instance by opening a shutter so that the beam can enter the detector surface.
  • the temperature is controlled, preferably during the whole measurement to get the data in constant conditions of the tem- perature and/or pressure.
  • the temperature can be checked and controlled also in other parts than indicated.
  • the pressure P can be controlled, even so to fine tune the wavelength by using the relationship between the pressure and the wavelength.
  • the photon radiation is converted to electron-hole pairs with the internal quantum efficiency (IQE) defined rate.
  • IQE internal quantum efficiency
  • the current is measured to yield the power, by an outer circuit.
  • the conversion producing hole and/or electron current is measured and averaged in the averaging phase; at least on a part of the duty cycle of the radiation beam, the average is converted to power in a calculating phase, in which also anomalies of the reality from the ideal are to be estimated for the maximum accuracy.
  • the power measurement data is stored and/or reported for a further process- ing of the data.
  • phase duration may vary from an application or use to another, but is not limited in such a way.
  • there can be overlapping phases and circularly connected buffering can be used in order to increase the efficiency of the cycle for the measurement program to go through, for data acquisition and processing optimization for instance.
  • the measuring arrangement com- prises a vacuum part in the optical path of the radiation.
  • the detector can be sealed into a chamber so to avoid the environment gases to interact with the detector and/or the radiation incoming to the detector.
  • the whole part of the optical path from the radiation source to the detector is in vacuum, including in vacuum also mirrors, lenses and other po- tentially present correction means to direct the radiation along the desired path towards the detector surfaces.
  • the optical path can comprise a part with a dry gas filling in a pressure that is lower than the atmospheric pressure according to one embodiment, but according to another embodiment larger pressure P, say 1 ,5 ' 100 bars can be used for the gas for ad- justing the optical density of the medium in the 113.
  • the gas filling can be chosen so that it does not influence on the radiation at all, or, has a minimum influence as possible according to an embodiment in a low pressure.
  • the optical path can comprise a wave guide which is embodied as fibre or a liquid.
  • the fibre can be ar- ranged to comprise a cavity for stimulated emission, and thus as a source for the radiation.
  • optical path it may be advantageous to use very long optical path, i.e in cases which measure of power in conditions where the detector according to an embodiment of the invention is supposed to be used, but the optical path is at least partly non-accessible because of high temperature, a distance, an astronomical distance, or because of bio-hazard, or radioactive contamination originated radiation.
  • the optical path could at least partly comprise the medium between the source of the radiation to be used in the power measurement and the detector according to an embodiment of the invention.
  • n ⁇ is the refractive index of the first medium ⁇
  • n D is the refractive index of the second medium D
  • Dj 7 is the angle of incidence
  • Dh is the re- fraction angle calculated according to the SnellDs law.
  • the refractive indices may contain an imaginary part for media with absorption.
  • the order of subscripts ⁇ D indicates the direction of propagation of light at the interface.
  • the amplitude reflection coefficient of p polarized light for a thin film on a substrate is
  • Equation (7) is periodic in terms of the film thickness D with period
  • a silicon dioxide thin film on silicon substrate in vacuum is considered to be used as an example for an absolute power measurement with a reference to example 2 on the reflection coefficient angular dependence.
  • reflectances as a function of angle of incidence were calculated for a detector structure to be utilised for absolute power measurement for monochromatic wavelengths with the indicated thicknesses of the oxide layer.
  • the equations were used for optimization to achieve the maximum EQE at the minimum reflectance.
  • the optimization algorithm was used to drive an adjustment arrangement arranged to adjust the angle of incidence so that the beam meets the detector at Brewster angle.
  • a thin film thickness of D 2908 nm then produces low intensity reflection for p po- larized light at the Brewster angle for wavelengths . . . 488 nm, 529 nm, 576 nm, 633 nm, 703 nm, 790 nm ...
  • This result is useful since frequently used fixed laser wavelengths 488 nm and 633 nm can then be used with low reflection of the same thin film sample.
  • Such a favourable situation can be obtained because c/(488 nm)/d(633 nm) is close to the ratio 10/13. Similar ratios of small integers can be found for other multiplets of convenient laser wavelengths, which allows radiation power measurements at several fixed wavelengths using the same detector with angular adjustment at the desired wavelength.
  • Example 2 reflectance as a function of angle of incidence at certain wave- lengths
  • Fig. 1 OA and 1 OB respectively illustrate reflectance as a function of angle of incidence for a 500 nm (Fig 10A) and 800 nm (Fig 10B) photon radiation from a Si diode surface with various indicated oxide layer thicknesses according to the figure. Equations 5-8 shown in example 1 are used in the determinations. The oxide layer thickness is shown at the right hand side down corner in nanometers (nm). The radiation in the example was assumed to be p-polahzed for the indicated radiation. Although a curve appears to meet the zero reflectance, it does not in practice. It is also same way for the minima in the Figs 10B and 10C, too. This is because of non-zero imaginary part of the silicon substrate referactive index.
  • Fig. 10C demonstrates reflectance as a function of the angle of incidence for a Si diode surface with various indicated oxide layer thicknesses in range of 2900-2916 nm. The figure also helps to understand an embodiment of the invention that uses a larger thickness for the oxide layer for standard fixed laser wavelengths to be used in a detector that has a structure according to an example of Fig. 11 and/or Fig.1.
  • the photon radiation is indicated in Fig. 11 by ⁇ , ⁇ l, ⁇ 2 and ⁇ 3, in several aspects of the detector.
  • the point 104 is the reflection point of the inputted photons at a detector surface part.
  • the portion 105 of radiation is a forward reflected portion ⁇ l that can be stronger than the scattered rays 106.
  • the layer 301 is silicon dioxide layer, and the pure silicon body is indicated by the numerals 107 and 118.
  • the ⁇ 2 illustrates a wave guide mode propagating in the oxide layer. Such wave guide modes can appear into the oxide layer 301 because of scattering from atoms, dislocations and/or other imperfections potentially present in the structure.
  • the detector can in an embodiment of the invention have DBR structure (203) or a reflector (202, 210, and/or 211 ) that reflects the ⁇ 2 type photons into such a path that leads them into the pure silicon body 107.
  • a reflector 211 can be formed near the edge by a wedge cavity in the oxide layer.
  • Another kind of reflector can be formed by a dendrite ridge demon- strated by the serrated ridge cross section 210.
  • the DBR structure 203 is a periodic grating that can be present optionally or in addition to the 202.
  • the layer edges of the layer 301 can be rounded and polished so to reflect photons better back, and thus to the path leading into the pure silicon body 107.
  • the photon ⁇ 3 demonstrates a photon with photon energy that converts to electric energy in form of a photocurrent, appearing as the energy that belongs to the pair of electron and hole (e ⁇ , h + ).
  • the distance of the photon ⁇ 3 travelled can be quite long, even several hundreds of micrometers.
  • the detector body thickness can be that of a silicon wafer, in order about 0,5 mm, for the 118 and/or for the part 107 in an appropriate embodiment.
  • a detector structure has been embodied according to Fig. 1.
  • the detector struc- ture has a detector part 118 that has a silicon substrate body made of pure silicon in planar geometry.
  • the detector part 118 is arranged to be adjustable in respect to the entrance aperture for the beam 103 to enter at the Brewster angle in to the detector structure, so enabling to utilize the maximum EQE of the silicon body at the wavelength of the incoming radiation.
  • the spot 104 is in the center of the spherical part 107.
  • the part 107 is embodied as a mirror with very high reflectance as arranged to focus by reflection the diffuse radiation to a spot on a detector.
  • the spot does not necessarily be exactly the same as the spot 104 in which the diffuse and/or specular reflected beam parts are collected, especially in such an embodi- ment variant in which the part 107 does not move with the detector part 118.
  • the opening is arranged so that the opening has a well known area with high accuracy and operates as a collimator part. The reflected parts of the radiation are collected onto the detector part 118.
  • the detector structure comprises in addition to that shown in example 4 also a mirror at the oxide layer edge, DBR-structure, diffraction grating or a combination thereof so arranged that the modes of the radiation that propagate in the oxide layer in wave guide mode are directed into the silicon body to and/or back to the original direction to utilise the high IQE as much as possible.
  • Example 6 a mirror at the oxide layer edge, DBR-structure, diffraction grating or a combination thereof so arranged that the modes of the radiation that propagate in the oxide layer in wave guide mode are directed into the silicon body to and/or back to the original direction to utilise the high IQE as much as possible.
  • the set up is similar to that shown in example 4, but differs from that so that the mirror 107 has been replaced by a detector having the oxide layer and a silicon body structure but also the shape of the mirror 107 in example 4, and thus the de- tector is able to focus the reflected radiation as in example 4 back to the detector part 118, but can also operate as detector, so enhancing the EQE.
  • the detector part 107 can be coupled in parallel with the detector part 118.
  • the mirror 107 can act as a secondary detector or a part of the detector, depending on the desire the secondary detector 107 is used in the embodi- ment in question as a separately coupled or in parallel with the detector 118.
  • Fig 4 gives further examples on such embodiments.
  • At least one of the parts 118 and 107 has the detector structure comprising in addition to that shown in example 4 also a mirror at the oxide layer edge, DBR-structure, diffraction grating or a combination thereof so arranged that the modes of the radiation that propagate in the oxide layer in wave guide mode are directed into the silicon body to and/or back to the original direction to utilise the high IQE as much as possible.
  • At least one of the parts 118 and 107 is arranged to be tiltable/pivotable in respect to the entering beam 103 from the entrance opening for the beam to meet the detector part 118 in Brewster angle. Because of the aperture system for the entering beam, this means that in embodiments in which the aperture or opening for beam 103 has essentially the same cross section area, the 107 is advantageously moved along to the part 118 for the Brewster angle with the particular wavelength of the radiation beam 103.
  • the part 118 has locking means arranged to lock the geometry for the Brewster angle for the radiation at the wavelength.
  • the part 107 has locking means to lock according to the part 118 for the beam to meet the part 118 at the Brewster angle.
  • the detector piece 118 is arranged to be fixed but the 113 is arranged to move in respect to the 111 via a flexible joint 117.
  • the movement and/or fixation of the parts 113 and 111 in respect of each other are not limited as such.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Optics & Photonics (AREA)
  • Light Receiving Elements (AREA)
  • Photometry And Measurement Of Optical Pulse Characteristics (AREA)

Abstract

L'invention concerne une mesure de puissance absolue à rendement quantique interne et/ou externe élevé pour détecteur comprenant au moins une couche de film (301) munie d'un substrat (118) formant ainsi une structure pour guider un rayonnement (g) en deçà d'une longueur d'onde dans un intervalle de longueur d'onde ; et des moyens (202, 203) agencés pour faire absorber au moins une partie dudit rayonnement (g) dans le corps de détecteur (118) par conversion de l'énergie desdits photons de rayonnement (g3) en énergie d'un courant électrique (h+, e') dans une température de fonctionnement (T) du détecteur. L'invention concerne aussi un procédé, un arrangement de mesure et un système à utiliser avec ledit détecteur.
EP08761717.1A 2007-05-31 2008-06-02 Mesure de puissance de rayonnement absolue Withdrawn EP2160766A4 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI20070429A FI125849B (fi) 2007-05-31 2007-05-31 Absoluuttinen säteilytehon mittaus
PCT/FI2008/050321 WO2008145829A1 (fr) 2007-05-31 2008-06-02 Mesure de puissance de rayonnement absolue

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EP2160766A1 true EP2160766A1 (fr) 2010-03-10
EP2160766A4 EP2160766A4 (fr) 2014-06-11

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4096387A (en) * 1976-12-09 1978-06-20 Rca Corporation Ultraviolet radiation detector
CH669050A5 (de) * 1985-05-29 1989-02-15 Oerlikon Buehrle Holding Ag Sensor zum nachweis von aenderungen der brechzahl einer festen oder fluessigen messsubstanz.
US5281804A (en) * 1992-08-06 1994-01-25 Fujitsu Ltd. Mirror apparatus for increasing light absorption efficiency of an optical detector
US20040033025A1 (en) * 2002-08-15 2004-02-19 Richard Fred Vincent Orthogonal coupled transceiver
US20040169245A1 (en) * 2001-11-05 2004-09-02 The Trustees Of Boston University Reflective layer buried in silicon and method of fabrication

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3506835A (en) * 1967-08-01 1970-04-14 Zenith Radio Corp Photo-detector signal-translating device
US3567948A (en) 1969-04-14 1971-03-02 Us Navy Method and apparatus for improving the quantum efficiency of phototubes
JPS596582A (ja) * 1982-07-05 1984-01-13 Mitsubishi Electric Corp 電源装置
US4681450A (en) * 1985-06-21 1987-07-21 Research Corporation Photodetector arrangement for measuring the state of polarization of light
US4782382A (en) * 1986-10-17 1988-11-01 Applied Solar Energy Corporation High quantum efficiency photodiode device
DE3920219A1 (de) * 1989-06-21 1991-01-10 Licentia Gmbh Betrieb eines optischen detektors bzw. optischer detektor geeignet fuer diesen betrieb
US5291055A (en) * 1992-01-28 1994-03-01 The United States Of America As Represented By The Administrator Of National Aeronautics And Space Administration Resonant infrared detector with substantially unit quantum efficiency

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4096387A (en) * 1976-12-09 1978-06-20 Rca Corporation Ultraviolet radiation detector
CH669050A5 (de) * 1985-05-29 1989-02-15 Oerlikon Buehrle Holding Ag Sensor zum nachweis von aenderungen der brechzahl einer festen oder fluessigen messsubstanz.
US5281804A (en) * 1992-08-06 1994-01-25 Fujitsu Ltd. Mirror apparatus for increasing light absorption efficiency of an optical detector
US20040169245A1 (en) * 2001-11-05 2004-09-02 The Trustees Of Boston University Reflective layer buried in silicon and method of fabrication
US20040033025A1 (en) * 2002-08-15 2004-02-19 Richard Fred Vincent Orthogonal coupled transceiver

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO2008145829A1 *

Also Published As

Publication number Publication date
WO2008145829A1 (fr) 2008-12-04
FI20070429A0 (fi) 2007-05-31
EP2160766A4 (fr) 2014-06-11
FI20070429A (fi) 2008-12-01
FI125849B (fi) 2016-03-15

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