Data Acquisition- Sensor Characteristics- Physical Principles of Sensing- Optical Components of Sensors- Interface Electronic Circuits- Occupancy and Motion Detectors- Position, Displacement, and Level- Velocity and Accleration- Force, Strain and Tactile Sensors- Pressure Sensors- Flow Sensors- Acoustic Sensors- Humidity and Moisture Sensors- Light Detectors- Radiation Detectors- Temperature Sensors- Chemical Sensors- Sensor Technologies- Appendix

/pdf/handbook-of-modern-sensors-4j39sae1hv.pdf

Handbook of modern sensors

Recent developments in the area of biological detection by optical sensing of molecular oxygen (O2) are reviewed, with particular emphasis on the quenched-phosphorescence O2 sensing technique. Following a brief introduction to the main principles, materials and formats of sensor technology, the main groups of applications targeted to biological detection using an O2 transducer are described. These groups include: enzymatic assays; analysis of respiration of mammalian and microbial cells, small organisms and plants; food and microbial safety; monitoring of oxygenation in cell cultures, 3D models of live tissue, bioreactors and fluidic chips; ex vivo and in vivo O2 measurements; trace O2 analysis. For these systems, which enable a range of new bioanalytical tasks with different samples and models in a minimally invasive, contact-less manner, with high sensitivity, flexibility and imaging capabilities in 2D and 3D, relevant practical examples are presented and their merits and limitations discussed. An outlook of future scientific and technological developments in the field is also provided.

Biological detection by optical oxygen sensing

A review of recent progress in signal processing, sensor developments and multiplexing techniques for fibre optic low-coherence interferometry is presented, with an emphasis on the new developments in this field which have the potential to be exploited for practical applications.

https://iopscience.iop.org/article/10.1088/0957-0233/7/7/001/pdf

Recent progress in fibre optic low-coherence interferometry

Remarkable developments can be seen in the field of optical fibre biosensors in the last decade. More sensors for specific analytes have been reported, novel sensing chemistries or transduction principles have been introduced, and applications in various analytical fields have been realised. This review consists of papers mainly reported in the last decade and presents about applications of optical fiber biosensors. Discussions on the trends in optical fiber biosensor applications in real samples are enumerated.

/pdf/recent-development-in-optical-fiber-biosensors-425igzxybu.pdf

Recent Development in Optical Fiber Biosensors

This is the first comprehensive review on methods and materials for use in optical sensing of pH values and on applications of such sensors. The Review starts with an introduction that contains subsections on the definition of the pH value, a brief look back on optical methods for sensing of pH, on the effects of ionic strength on pH values and pKa values, on the selectivity, sensitivity, precision, dynamic ranges, and temperature dependence of such sensors. Commonly used optical sensing schemes are covered in a next main chapter, with subsections on methods based on absorptiometry, reflectometry, luminescence, refractive index, surface plasmon resonance, photonic crystals, turbidity, mechanical displacement, interferometry, and solvatochromism. This is followed by sections on absorptiometric and luminescent molecular probes for use pH in sensors. Further large sections cover polymeric hosts and supports, and methods for immobilization of indicator dyes. Further and more specific sections summarize the state of the art in materials with dual functionality (indicator and host), nanomaterials, sensors based on upconversion and 2-photon absorption, multiparameter sensors, imaging, and sensors for extreme pH values. A chapter on the many sensing formats has subsections on planar, fiber optic, evanescent wave, refractive index, surface plasmon resonance and holography based sensor designs, and on distributed sensing. Another section summarizes selected applications in areas, such as medicine, biology, oceanography, bioprocess monitoring, corrosion studies, on the use of pH sensors as transducers in biosensors and chemical sensors, and their integration into flow-injection analyzers, microfluidic devices, and lab-on-a-chip systems. An extra section is devoted to current challenges, with subsections on challenges of general nature and those of specific nature. A concluding section gives an outlook on potential future trends and perspectives.

Optical Sensing and Imaging of pH Values: Spectroscopies, Materials, and Applications

Fiber optic Fabry-Perot sensors have been developed whose optical reflectance varies with optical cavity depth (pressure) or with change in a material's refractive index (temperature). These sensors employ a unique combination of features: they are interrogated by an LED; they are designed to operate within a single reflectance cycle; and their returned light is analyzed by a dichroic ratio technique. The sensors use a step index glass fiber and are relatively insensitive to absolute light levels and fiber bending. They have an expanded linear operating range and can be built for low cost disposable applications. Sensor performance meets or exceeds established medical requirements. >

Development of medical pressure and temperature sensors employing optical spectrum modulation

A new fiber-optic pH sensor system has been developed. The sensor uses an absorptive indicator compound with a long wavelength absorption peak near 625 nm; change in absorption over the pH range 6.8 to 7.8 is reasonably linear. The sensor is interrogated by a pulsed, red LED. The return light signal is split into short- and long-wavelength components with a dichroic mirror; the respective signals are detected by photodiodes, and their photocurrents are used to form a radiometric output signal. In laboratory tests, the sensor system provided resolution of 0.01 pH, accuracy of +or-0.01 pH, and response time of 30-40 s. Following gamma sterilization, laboratory sensor testing with heparinized human blood yielded excellent agreement with a clinical blood gas analyzer. Excellent sensor performance and low cost, solid-state instrumentation are hallmarks of this sensor-system design. >

Development of a medical fiber-optic pH sensor based on optical absorption

A fiber-optic oxygen sensor has been developed for use in medical applications. The sensor's viologen indicator becomes strongly absorbant after brief UV stimulation, and then returns to the transparent state. The rate of indicator return to transparency is proportional to the local oxygen concentration. Indicator absorbance is monitored with a red LED and receiving photodiode, and absorbance data are processed by a dedicated CPU. The solid-state sensor system has performance comparable to existing oxygen measurement techniques, and may be applicable for both in vitro and in vivo oxygen measurements. >

Development of a medical fiber-optic oxygen sensor based on optical absorption change

The refractive index of a material such as silicon changes rapidly with temperature at wavelengths near the band edge. This phenomenon can be used to sense temperature if the silicon or other material is used as a Fabry-Perot etalon. As temperature changes and the index varies, the etalon's spectral reflection characteristics will be affected. Using this effect and a spectral distribution readout technique it is possible to construct an optical temperature sensor with many desirable properties. These include a wide temperature range, typically -100 to + 400°C, long-term stability, insensitivity to connector and fiber losses, tolerance of fiber bending effects and rapid response. These sensors are fabricated using techniques similar to those used to manufacture semiconductor devices. This results in low production costs and the ability to produce sensors with reproducible performance.

Fiber Optic Temperature Sensor Using Spectral Modulation

A dual function sensor system has been developed for measuring pressure and temperature at the tip of a single optical fiber. The sensor contains three parts: a filter band-edge shift temperature sensor, a short-wavelength-reflecting dichroic filter, and a diaphragm-based spectral modulation pressure sensor. The sensor system uses a separate and distinct light-emitting diode (LED) for interrogating each sensor, three 100/140 mm step-index fused couplers for managing light, and separate paired photodiode assemblies for analyzing the return light signal from each sensor. In bench tests, each sensor performed to specification and there was no crosstalk between sensors. This sensor design has potential catheter applications where catheter size must be kept to an absolute minimum. >

E. Saaski

Papers

Development of medical pressure and temperature sensors employing optical spectrum modulation

Development of a medical fiber-optic pH sensor based on optical absorption

Development of a medical fiber-optic oxygen sensor based on optical absorption change

Fiber Optic Temperature Sensor Using Spectral Modulation

Development of a dual function sensor system for measuring pressure and temperature at the tip of a single optical fiber