Abstract: A system for measuring a parameter, such as temperature, includes a sensor of that parameter, such as a luminescent material based sensor at an end of an optical fiber, and an electro-optic module connected to the sensor, such as through the optical fiber, in order to measure changes in some sensor characteristic, such as luminescence decay time, that is related to the parameter to which the sensor is being subjected. The sensor is designed to have a relationship of such a characteristic to the parameter being measured that is matched to the ability of the module to measure the characteristic. In a temperature measurement system example, a luminescent material is chosen with decay time vs.

Abstract: A luminescence-based integrated optical and electronic system for measuring temperature or some other parameter from the decay time of a luminescent sensor is disclosed. A high bandwidth, low noise amplifier applies a detected decaying luminescent signal to a digital system that acquires that signal and processes it in order to determine its decay time characteristics that are related to temperature or another parameter being measured. The digital signal processing includes use of a digital curve-fitting technique. A preferred luminescent material for temperature measurement is a chromium-doped yttrium gallium garnet material. The entire optical and electronic portions of the measuring system can be accommodated on a small single circuit card.

Abstract: Fiberoptic sensors of various configurations are provided for measuring the magnitude of the electric or magnetic fields, and thereby the power, at local points within a relatively high-power electromagnetic heating environment such as occurs, for example, in a microwave oven or an industrial microwave processing chamber. Each type of sensor includes one element that is heated by either the oscillating electric or magnetic field, and an optical temperature measuring element positioned to be heated by the first element, its temperature being optically determined by an instrument to which an opposite end of the optical fiber length is connected.

Abstract: Fiberoptic sensors of various configurations are provided for measuring the magnitude of the electric or magnetic fields, and thereby the power, at local points within a relatively high-power electromagnetic heating environment such as occurs, for example, in a microwave oven or an industrial microwave processing chamber. Each type of sensor includes one element that is heated by either the oscillating electric or magnetic field, and an optical temperature measuring element positioned to be heated by the first element, its temperature being optically determined by an instrument to which an opposite end of the optical fiber length is connected.

Abstract: A luminescence-based integrated optical and electronic system for measuring temperature or some other parameter from the decay time of a luminescent sensor is disclosed. A high bandwidth, low noise amplifier applies a detected decaying luminescent signal to a digital system that acquires that signal and processes it in order to determine its decay time characteristics that are related to temperature or another parameter being measured. The digital signal processing includes use of a digital curve-fitting technique. A preferred luminescent material for temperature measurement is a chromium-doped yttrium gallium garnet material. The entire optical and electronic portions of the measuring system can be accommodated on a small single circuit card.

Abstract: Several specific types of optical sensors capable of measuring temperature, pressure, force, acceleration, radiation and electrical fields, fluid level, vapor pressure, and the like, are disclosed, along with an electro-optical system for detecting the optical signal developed by the sensor. One such probe utilizes a convex shaped structure consisting of an elastomeric material attached to an end of an optical fiber, the elastomeric material being coated with a luminescent material, a combination that is capable of measuring both temperature and pressure. Such a probe is also specifically adapted for measuring surface temperature by making a good physical contact with the surface being measured. Another such probe utilizes a similar structure but of a non-elastomeric material for the purpose of detecting both temperature and either index of refraction or vapor pressure changes.

Abstract: A single sensor is provided as part of a fiberoptic probe to measure up to three parameters, namely pressure (or force or displacement), temperature, and heat flow or fluid velocity. A solid elastomeric optical element is formed at the end of optical fiber transmission medium, and adjacent light reflective and temperature dependent materials are formed on the resulting convex surface of the optical element. The amount of light reflected is proportional to the force or pressure against the element. The temperature dependent material is preferably a luminescent material. Over the luminescent material is formed a layer of material that is absorptive of infrared radiation, thereby allowing a determination of characteristics of heat or fluid flow by measuring the rate at which heat is carried away from the infrared heated layer. The sensor can be formed at the end of a single optical fiber, thereby having extensive applications where a very small sensor is required.

Abstract: Several specific types of optical sensors capable of measuring temperature, pressure, force, acceleration, radiation and electrical fields, fluid level, vapor pressure, and the like, are disclosed, along with an electro-optical system for detecting the optical signal developed by the sensor. One such probe utilizes a convex shaped structure consisting of an elastomeric material attached to an end of an optical fiber, the elastomeric material being coated with a luminescent material, a combination that is capable of measuring both temperature and pressure. Such a probe is also specifically adapted for measuring surface temperature by making a good physical contact with the surface being measured. Another such probe utilizes a similar structure but of a non-elastomeric material for the purpose of detecting both temperature and either index of refraction or vapor pressure changes.

Abstract: A technique of measuring very high temperatures by positioning a blackbody sensor in thermal communication with an environment or object whose temperature is to be measured, communicating infrared emissions having an energy level proportional to such temperature from the sensor to an infrared absorber positioned a distance away from the sensor where the ambient temperature is significantly reduced, and then optically measuring the temperature of the absorber by a technique that uses visible or near visible optical radiation, such as one using a luminescent sensor. The measured temperature of the absorber is proportional to that of the blackbody sensor.

Abstract: An optical temperature measurement technique that utilizes the decaying luminescent intensity characteristic of a sensor composed of a luminescent material that is excited to luminescence by a light pulse or other periodic or other intermittent source of radiation. The luminescent emissions of a preferred sensor exhibit an approximately exponential decay with time that is the average of a distribution of chemically reproducible crystallites and are repeatable with a high degree of accuracy regardless of excitation level or prior temperature history of the sensor.

Abstract: An optical fiber temperature sensing probe for implantation into a human body or other object that is being heated either by ultrasonic radiation alone or by a combination of ultrasonic and electromagnetic (radio frequency or microwave) energy. Several embodiments are described of probes adapted to measure temperature in an ultrasound field without errors being introduced by direct absorption of ultrasonic energy or by viscous heating, even when plastic fiber is utilized.

Abstract: Several specific types of optical sensors capable of measuring temperature, pressure, force, acceleration, radiation and electrical fields, fluid level, vapor pressure, and the like, are disclosed, along with an electro-optical system for detecting the optical signal developed by the sensor. One such probe utilizes a convex shaped structure consisting of an elastomeric material attached to an end of an optical fiber, the elastomeric material being coated with a luminescent material, a combination that is capable of measuring both temperature and pressure. Such a probe is also specifically adapted for measuring surface temperature by making a good physical contact with the surface being measured. Another such probe utilizes a similar structure but of a non-elastomeric material for the purpose of detecting both temperature and either index of refraction of vapor pressure changes.

Abstract: An optical temperature measurement technique that utilizes the decaying luminescent intensity characteristic of a sensor composed of a luminescent material that is excited to luminescence by a light pulse or other periodic or other intermittent source of radiation. The luminescent emissions of a preferred sensor exhibit an approximately exponential decay with time that is the average of a distribution of chemically reproducible crystallites and are repeatable with a high degree of accuracy regardless of excitation level or prior temperature history of the sensor.

Abstract: An optical fiber temperature sensing probe is implanted into a human body or other object that is being heated, either by ultrasonic radiation alone or by a combination of ultrasonic and electromagnetic (radio frequency or microwave) energy. In order to measure temperature in an ultrasound field without the probe introducing errors, the probe is made to be substantially thermally non-conducting, made of materials that do not absorb compressional energy, and has a small diameter relative to the length of the ultrasonic heating waves.