公开(公告)号：US4262198A

公开(公告)日：1981-04-14

申请号：US61822

申请日：1979-07-30

申请人： Amitava Gupta ,  Su-Don Hong ,  Jovan Moacanin

发明人： Amitava Gupta ,  Su-Don Hong ,  Jovan Moacanin

IPC分类号： G01J5/58 ,  G01N21/17 ,  G01J1/00 ,  H01J31/50

CPC分类号： G01N21/171 ,  G01J5/58

摘要： A method and apparatus for detecting optical radiation by optically monitoring temperature changes in a microvolume caused by absorption of optical radiation to be detected. More specifically, a thermal lens-forming material is provided which has first and second opposite, substantially parallel surfaces. A reflective coating is formed on the first surface, and a radiation-absorbing coating is formed on the reflective coating. Chopped, incoming optical radiation to be detected is directed to irradiate a small portion of the radiation-absorbing coating. Heat generated in this small area is conducted to the lens-forming material through the reflective coating, thereby raising the temperature of a small portion of the lens-forming material and causing a thermal lens to be formed therein. The thus-formed thermal lens is optically detected by irradiating the thermal lens by a collimated light beam. The light beam, after having passed through the thermal lens, is reflected by the reflective coating back through the thermal lens, and directed by a beam splitter to an optical detector. In a further embodiment of the invention, the optical radiation to be detected is passed through a template, thereby defining a plurality of areas on the radiation absorbing coating to be irradiated. A corresponding template is provided in a spread, collimated light beam to define a plurality of coherent light beams, each of which passes through a thermal lens in the lens-forming material. Each beam is then reflected by the reflective coating, passes back through the thermal lens, and is directed by a beam splitter to an optical detector. The invention is particularly useful as a broadband infrared detector.

摘要翻译： 通过光学地监测由待检测的光辐射的吸收引起的微量体积的温度变化来检测光辐射的方法和装置。 更具体地，提供了具有第一和第二相对的基本上平行的表面的热透镜形成材料。 在第一表面上形成反射涂层，并且在反射涂层上形成辐射吸收涂层。 被切割的待检测的入射光辐射被照射到辐射吸收涂层的一小部分。 在该小区域产生的热量通过反射涂层传导到透镜形成材料，从而提高透镜形成材料的一小部分的温度，并在其中形成热透镜。 通过用准直光束照射热透镜来光学地检测由此形成的热透镜。 光束在穿过热透镜之后被反射涂层反射回热透镜，由光束分离器引导到光学检测器。 在本发明的另一实施例中，待检测的光辐射通过模板，从而限定待辐射的辐射吸收涂层上的多个区域。 在扩展的准直光束中提供相应的模板以限定多个相干光束，每个相干光束通过透镜形成材料中的热透镜。 然后每个光束被反射涂层反射，返回穿过热透镜，并由光束分离器引导到光学检测器。 本发明作为宽带红外探测器特别有用。

公开(公告)号：US4243327A

公开(公告)日：1981-01-06

申请号：US8211

申请日：1979-01-31

申请人： Robert A. Administrator of the National Aeronautics and Space Administration, with respect to an invention of Frosch ,  Jovan Moacanin ,  Amitava Gupta ,  Su-don Hong

发明人： Robert A. Administrator of the National Aeronautics and Space Administration, with respect to an invention of Frosch ,  Jovan Moacanin ,  Amitava Gupta ,  Su-don Hong

IPC分类号： G01N21/17 ,  G01N25/18 ,  G01N21/01

CPC分类号： G01N21/171 ,  G01N25/18

摘要： A method and apparatus for measuring thermal diffusivity and molecular relaxation processes in a sample material utilizing two light beams, one being a pulsed laser light beam for forming a thermal lens in the sample material, and the other being a relatively low power probe light beam for measuring changes in the refractive index of the sample material during formation and dissipation of the thermal lens. More specifically, a sample material is irradiated by relatively high power, short pulses from a dye laser. Energy from the pulses is absorbed by the sample material, thereby forming a thermal lens in the area of absorption. The pulse repetition rate is chosen so that the thermal lens is substantially dissipated by the time the next pulse reaches the sample material. A probe light beam, which in a specific embodiment is a relatively low power, continuous wave (cw) laser beam, irradiates the thermal lens formed in the sample material. The intensity characteristics of the probe light beam subsequent to irradiation of the thermal lens is related to changes in the refractive index of the sample material as the thermal lens is formed and dissipated. A plot of the changes in refractive index as a function of time during formation of the thermal lens as reflected by changes in intensity of the probe beam, provides a curve related to molecular relaxation characteristics of the material, and a plot during dissipation of the thermal lens provides a curve related to the thermal diffusivity of the sample material.

摘要翻译： 一种利用两个光束测量样品材料中的热扩散率和分子弛豫过程的方法和装置，一种是用于在样品材料中形成热透镜的脉冲激光束，另一种是相对低功率的探测光束， 测量在热透镜的形成和耗散期间样品材料的折射率的变化。 更具体地，通过来自染料激光器的相对高功率的短脉冲照射样品材料。 来自脉冲的能量被样品材料吸收，从而在吸收区域形成热透镜。 选择脉冲重复率，使得热透镜在下一个脉冲到达样品材料的时间基本消散。 探针光束在特定实施例中是相对低功率的连续波（cw）激光束照射形成在样品材料中的热透镜。 在透镜的照射之后的探测光束的强度特性与形成和散发热透镜时的样品材料的折射率的变化有关。 作为由透镜的强度变化所反射的热透镜形成时的折射率随时间的变化的曲线图，提供了与材料的分子弛豫特性相关的曲线，以及热耗散期间的曲线 透镜提供与样品材料的热扩散率相关的曲线。