In this paper, silicon-based micro and subwavelength optical elements based on a free-standing silicon nitride (SiNx)
membrane are achieved. These elements, including gratings, microlenses, and holographic optical elements (HOEs), are
designed and used within the visible and infrared regions. These devices can be used as collimators, reflectors, and
wavelength-dependent filters with advantages of simple structure, high efficiency and feasibility to integrate with other
elements into a micro-system chip. In order to demonstrate the advantage of micro-optics of free-standing SiNx
membrane type in integration, a miniaturized optical pickup head module based on a stacked micro-optical system is
developed. This module consisted of a laser diode, a reflector, a grating, a holographic optical element, and some
aspherical Fresnel lenses. The novel microoptical system can overcome the problems encountered in other microoptical
systems such as off-axis aberration, lower optical efficiency or durability, integration and even in fabrication. A focal
spot with a FWHM diameter of 3.3 μm is obtained while the diffraction limited full-width at half-maximum (FWHM) is
0.7 μm. To extend the advantage of micro-optics of free-standing SiNx membrane, the subwavelength optical elements
base on guided-mode resonance is also developed. With various Si-based structures, the filter possesses numerous
properties such as variable bandwidths, low sideband, flattop, and etc. They are also applied as biosensors to detect the
hybridization process of bio reaction for their high sensitivity. The results show that micro and subwavelength optical
elements fabricated on Si-based material will be a candidate for emerging silicon micro-photonics.
This study will discuss the heat dissipation effect of light emitting diode (LED) device applied a commercial miniature heat pipe (MHP). For lowering the thermal resistance of LED, the MHP can reduce the working temperature and raise the allowable input power of LED chip obviously. By comparing with a copper rod, the LED temperature was decreased about 19% at 1.59W input power and the LED power was increased about 43% under 118°C chip temperature. On the other hand, the thermal resistance of LED also can be reduced by using a thinner slug. Moreover, the results showed that the thermal spreading effect was significant. The MHP could be used to avoid the hot spot of LED packaging due to its excellent heat spreading property. Simultaneously, a LED thermal simulation was carried out to verify the optimum value of slug thickness.