Page 41 -

30 1 From Optical MEMS to Micromechanical Photonics
direction, in which many devices are under development (black circles), as
seen in the same figure.
Much work is needed to reach the final goal. Good mechanical properties,
high speed, and strong power are foreseen for microdevices. Microassembly,
packing, and wiring techniques must be improved. Tribology on the microscale
must be studied to realize smooth motion.
In the following chapters, we highlight key technologies in the development
of future optical MEMS/micromechanical photonics devices and describe not
only theoretical and experimental results but also their fields of application.
Chap. 2 deals with LD closely aligned with a microstructure such as a di-
aphragm, a microcantilever and a slider. As examples, we examine extremely
short-external-cavity LDs such as a tunable LD, a resonant sensor and an
integrated optical head. Chap. 3 addresses optical tweezers. The new technol-
ogy is employed to manipulate various types of objects in a variety of research
and industrial fields. Chap. 4 deals with the design and fabrication of an op-
tical rotor and the evaluation of the mixingperformance of microliquids for a
future fluidic applications such as µ-TAS. In Chap. 5, the fundamentals and
applications of the near field induced on an object surface are described for
the future development of micromechanical photonics. This technology en-
ables us to carry out observing, reading/writing, and fabrication beyond the
wavelength resolution by accessing and controlling the near field.

Problems

1.1. Compare the methods of fabricatingoptical MEMS/micromechanical
photonics devices.
1.2. Explain the workingmechanism of a sacrificed layer in the fabrication of
microdevices.
1.3. Explain the problems to be solved for a miniaturized device.

1.4. Estimate the reduction of torque required to tilt a micromirror with a
50% reduction of the dimensions (the mirror is a × binareaandtthick).

1.5. Why does response time become fast in a microsystem?

1.6. Compare the methods of drivingmicromechanical photonics devices.
1.7. Predict the future technical trend of micromechanical photonics.