219 8. 2 Sensors 221 8. 3 Physical Sensors 222 8. 3. 1 Electrical
Sensing Means 223 8. 3. 2 Magnetic Field Methods 231 8. 3. 3 Optical
Methods 232 8. 4 Chemical Sensors 241 8. 4. 1 Electrical Gas and
Chemical Sensors 243 8. 4. 2 Guided-Optics Intrinsic Chemical Sensors
246 8. 4. 3 Extrinsic Chemical Sensors 250 8. 4. 4 Polymer Waveguide
Chemical Sensors 251 8. 4. 5 Surface Plasmon Chemical Sensors 252 8. 4.
6 Indicator-Mediated Extrinsic Sensing 253 8. 4. 7 Optical Biosensors
256 8. 4. 8 Ultrasonic Gas and Chemical Sensors 257 8. 4. 9 Intelligent
Sensors 258 8. 5 Connections/Links and Wiring 258 8. 5. 1 Optical Links
260 8. 5. 2 Requirement on the Processing Unit/Intelligence 262 8. 6
Actuators 263 8. 7 Signal Processing/Computing 264 8. 7. 1 Implicit
Computation 266 8. 7. 2 Explicit Computation 267 8. 8 References 274
Subject Index 279 Micro-Actuators (Electrical, Magnetic, Thermal,
Optical, Mechanical, and Chemical) It has become quite apparent that
sensors and actuators are the main bottleneck of the modem information
processing and control systems. Microprocessors and computers used to be
the main limiting element in most information processing systems. But
thanks to the enonnous progress in the microelectronics industry, most
information analysis tasks can be processed in real time. The data has
to be acquired by the processor in some form and processed and used to
produce some useful function in the real world.