SU638130A1

SU638130A1 - Thin-film interferometer

Info

Publication number: SU638130A1
Application number: SU762410265A
Authority: SU
Inventors: А.И. Гудзенко; Л.А. Осадчев; В.Ф. Теричев; А.А. Тищенко
Original assignee: Университет дружбы народов им.Патриса Лумумбы
Priority date: 1976-10-07
Filing date: 1976-10-07
Publication date: 1980-05-25

Description

'Изобретение относится к технике измерений в оптическом и субмиллиметровом диапазоне волн, в частности к конструкции тонкопленочных интерферометров, и может быть использовано для измерения малых изменений температуры, слабых потоков энергии, показателей преломления газов и жидкостей.'' The invention relates to techniques for measuring in the optical and submillimeter wavelength range, in particular to the design of thin-film interferometers, and can be used to measure small temperature changes, weak energy flows, refractive indices of gases and liquids.

Известны двухлучевые интерферометры, в которых два луча образуются при направлении излучения от источника света на границу раздела двух оптических элементов и затем интерферируют в некоторой области пространства [1].Two-beam interferometers are known in which two beams are formed when the radiation from the light source is directed to the interface of two optical elements and then interfere in a certain region of space [1].

Ближайшим к описываемому изобретению по технической сущности является тонкопленочный интерферометр, содержащий тонкопленочный диэлектрический волновод со скошенными входным и выходным концами, расположенный на подложке из пьезоэлектрика, показатель преломления материала которой меньше показателя преломления несущего слоя волновода Интерференционная картина, по виду кото рой судят об изменениях температуры прилегающей к несущему слою среды, о величине слабых' потоков энергии,, падающей на несущий слой, о показателе преломления жидкостей и газов, обтекающие несущий спой, наблюдается в области перекрытия сигнального и опорного пучков, зависящей от тщательного подбора скошенного профиля несущего слоя.The closest to the described invention by technical essence is a thin-film interferometer containing a thin-film dielectric waveguide with beveled input and output ends, located on a substrate of piezoelectric, the refractive index of which is less than the refractive index of the carrier layer of the waveguide. The interference pattern, by the form of which judges the changes in the temperature of the adjacent to the carrier layer of the medium, the magnitude of the weak energy flows incident on the carrier layer, and the refractive index of the liquid awns and gas flowing around the bearing sing observed in the overlapping area of the signal and reference beams, which depends on the careful selection of beveled profile of the carrier layer.

Однако ввиду д©контролируемости профиля несущего слоя в процессе изготовления волновода обеспечить перекрытие пучков на выходе таких интерферометров крайне трудно. Кроме того, в известном интерферометре отсутствует возможность обработки информации о.параметрах исследуемых процессов радиотехническими средствами,' что существенно снижает скорость и точность измерений.However, in view of the controllability of the profile of the carrier layer during the manufacture of the waveguide, it is extremely difficult to ensure overlapping beams at the output of such interferometers. In addition, in the known interferometer there is no possibility of processing information about the parameters of the processes under study by radio engineering means, which significantly reduces the speed and accuracy of measurements.

Целью изобретения является обеспечение контролируемого перекрытия интерферирующих пучков и обработки сигнала радиотехническими средствами.The aim of the invention is the provision of controlled overlapping of the interfering beams and signal processing by radio engineering means.

Нель достигается за счет того, что в предлагаемом устройстве на границе раздела волновода и подложки со стороны выходного конца волновода расположен возбудитель акустических поверхностных волн.Nel is achieved due to the fact that in the proposed device at the interface between the waveguide and the substrate from the output end of the waveguide is the pathogen of acoustic surface waves.

На чертеже изображен предлагаемый тонкопленочный интерферометр, содержащий тонкопленочный Диэлектрический волновод 1, расположенный на подложке 2 из пьезо- ι электрика. Скошенный профиль Зв начале вопноводаявпяется элементом ввода интерферометра. Со стороны выходного конца 4 . волновода расположен возбудитель 5 акустических поверхностных волн.The drawing shows the proposed thin-film interferometer containing a thin-film dielectric waveguide 1 located on a substrate 2 of a piezoelectric. The slanting profile of the sound at the beginning of the water is an input element of the interferometer. From the output end 4. the waveguide is the pathogen 5 of the acoustic surface waves.

Устройство работает следующим образом.The device operates as follows.

Излучение падающего пучка с частотой W (например от лазера) разделяется на два пучка на входном конце интерферомет>ра. При этом опорный пучок, образованный в результате отражения от границы раздела подложка - несущий слой, распространяется в подложке 2, а сигнальный пучок, представляющий собой волноводную оптическую вбпну, образуется в реВозможный диапазон Λθ изменений направления распространения сигнального, пучка, излученного в подложку, определяется диапазоном ΔΛ перестройки час₅ тоты колебаний в акустической поверхностной волне:The radiation of an incident beam with a frequency W (for example, from a laser) is divided into two beams at the input end of the interferometer> pa. In this case, the reference beam formed as a result of reflection from the substrate - carrier layer interface propagates in the substrate 2, and the signal beam, which is a waveguide optical PFN, is formed in a possible range Λθ of changes in the propagation direction of the signal beam emitted into the substrate, is determined by the range ΔΛ tuning time ₅ hours of vibration in an acoustic surface wave:

21ьл й д £3 ~ ...... . ,21st d £ 3 ~ ....... ,

Vk_Mn_n5in©Vk _M n _n 5in ©

Изменяя частотуД колебаний в акустической поверхностной волне (т. е. изменяя угол отклонения Q излученного в подложку сигнального пучка), можно до15 биться перекрытия опорного и сигнального пучков на выходе интерферометра. Излученный в подложку дифрагировайппий на бегущей акустической поверхностной волне сигнальный пучок имеет частотуBy changing the frequency of oscillations in an acoustic surface wave (i.e., by changing the deflection angle Q of the signal beam emitted into the substrate), it is possible to achieve overlapping of the reference and signal beams at the output of the interferometer. The signal beam emitted into the substrate by diffracting waves on a traveling acoustic surface wave has a frequency

W+Λ , что дает возможность осуществления гетеродинной обработки исследуемого сигнала, несущего информацию об изменении разности фаз сигнального и опорного пучков, по которой и судят об измене- ниях температуры прилегающей к несущему слою среды, о величине слабых потоэультате ввода излучения падающего пучка в несущий слой через его скошенный профиль. Поверхностная акустическая волна, возбуждаемая преобразователем 30 электрических колебаний в акустические, распространяется навстречу сигнальной оптической волне. При взаимодействии поверхностей акустической волны и оптической волноводной волны (сигнального 35 пучка) нарушается волноводный режим распространения оптической волны, и она излучается в подложку 2. Угол излучения в подложку зависит от частоты колебаний акустической волны Л: 40 •k в - ЙГС cos ---!W + Λ, which makes it possible to perform heterodyne processing of the studied signal, which carries information on the change in the phase difference of the signal and reference beams, which is used to judge the changes in the temperature adjacent to the carrier layer of the medium, and the weak values due to the input of the incident beam radiation into the carrier layer through his beveled profile. The surface acoustic wave excited by the transducer 30 of electrical vibrations into acoustic waves propagates towards the signal optical wave. When the surfaces of the acoustic wave and the optical waveguide wave (signal beam 35) interact, the waveguide mode of propagation of the optical wave is violated, and it is radiated into the substrate 2. The angle of radiation into the substrate depends on the frequency of the acoustic wave A: 40 • k in - GHS cos --- !

К И_и K _and

где V where v - скорость распространения - propagation speed акустической вопньу acoustic yell 45 45 5 5 показатель преломления под- refractive index ложки^ - волновое число для оптичес- spoons ^ is the wave number for optical кой волны в вакууме: wave in vacuum: - волновое число, характеризующее бегущую волну моды гл, распространяющуюся в волноводе со скоростью is the wave number characterizing the traveling wave of the hl mode propagating in the waveguide with a velocity 50 fifty

ков энергии, падающей на несущий слой, о показателе преломления жидкостей и газов, обтекающих несущий слой.of energy incident on the carrier layer, on the refractive index of liquids and gases flowing around the carrier layer.

Claims

The invention relates to a measurement technique in the oriTHieCKOM and submillimeter-wave range, in particular, to the design of thin-film interferometers, and can be used to measure small temperature changes, weak energy fluxes, and refractive indices of gases and liquids. Two-beam interferometers are known in which two beams are formed when the radiation is emitted from a light source to the interface between two optical elements and then interfere in a certain region of space l. The closest to the described invention is a technical entity that incorporates a film interferometer containing a thin-film dielectric waveguide with a skewed input and output ends, located on a piezoelectric substrate, the material preparification index of which ru is less than that of the carrier wave component 1, which is not the body that is part of the body, which is not the body, which is not the body, which is not the body, which is not the body, which is not the body, which is not the body, which is not the body, which is not the body, which is not the body, which is not the body part, and the body is not. t about changes in the temperature of the medium adjacent to the carrier layer, on the magnitude of weak energy fluxes 5 incident on the carrier, on the refractive index liquids and gases, flow around the supporting LAYER 5 cabling in the area of overlap of the signal and reference beams, resulting in a careful selection of the carrier profile of the carrier layer, however, in view of; We control (x; ti croc carrier layer in the waveguide fabrication process) it is extremely difficult to overlap the beams at the output of such interferometers. In addition, the known interferometer does not have the ability to process information about the parameters of the sun of the following processes by means of radio engineering. and accuracy of measurements. The aim of the invention is to provide controlled overlapping of the interfering beams and signal processing by radio-technical means, and 3 liesib is due to the fact that We assume that the exciton noBqpXHocTHbix exciter is located at the interface between the vospod and the substrate on the side of the Bypass of the end of the vent. the input of the interferometer. With CTqjOHH at the first end of the 4th waveguide, the causative agent of 5 acoustic waves is located, the device works as follows The incident beam from the frequency W (Hanpmviep from the laser) is divided into two beams at the input end of the interfermeter. At the same time, the reference beam, formed as a result of the donning of the interface through the carrier layer, is propagated in the subplate 2, and the signal beam, which is a waveguide optical array, is formed as a result of inputting the incident beam into the carrier beam through its beveled edge ( |) or “Surface acoustic,” a wave, excited by a transducer of electrical oscillations into acoustic waves, propagates in the opposite direction of the signal optical wave. When the surfaces of the acoustic wave and the optical water wave (signal beam) interact, the waveguide propagation mode of the optical wave is disturbed, and it is radiated into the substrate 2 ". The angle of radiation into the substrate depends on the oscillation frequency of the acoustic wave L: k -S. in arc COS k n. о n V is the propagation speed of the acoustic wave P the refractive index of the substrates: pg - $ ppd number for the optical wave in vacuum: the wave number characterizing the traveling wave of mode no, propagating in the waveguide with the velocity v CKoJ-k. 304 The possible range uQ of changes in the direction of propagation of a signal, beam emitted into the substrate is determined by the DL range of tuning the frequency of the oscillations in the acoustic surface wave:. Q By changing the frequency L of the oscillations in the acoustic surface wave (i.e. changing the angle of deviation Q of the signal beam emitted into the substrate), it is possible to achieve overlap of the reference and signal beams at the output of the interferometer. The signal beam radiated into the substrate of diffraction on a traveling acoustic surface wave has a frequency W + A, which makes it possible to carry out a single processing of the signal under study, carrying information about the change in the phase difference between the signal and reference ny4KOBs on which it is judged about the temperature changes adjacent to the carrier layer the medium, the magnitude of weak energy fluxes incident on the carrier layer, the refractive index of liquids and gases flowing around the carrier layer. Invention A thin-film interferometer for the optical and submillimeter wavelength range, comprising a piezoelectric substrate with a thin-film dielectric waveguide with a beveled input end located on it, in order to provide a controlled overlap of the interfering beams at the waveguide and substrate interface from the side the output end of the waveguide is the causative agent of acoustic surface waves. Sources of information taken into account in the examination 1. US Patent No. 3031914, cl, 356-110, published, 1962, 2 "Zolotov E, M. Thin-film interferometer. Quantum Electronics, 1976; V. 3, No. 2, S, 453,