Optical Resonator

    In recent years, high optical quality factor resonators have been used for many applications.
Some of these include those in optical telecommunication biological and mechanical sensing. References describe a detailed review of recent morphology dependent resonances (MDR) applications. The MDR are optical OPEN ACCESS Sensors 2014, 14 7042 modes that are observed in dielectric resonator, and are excited by coupling light from a tunable laser into the resonator using a single mode optical fiber. A simplified description of the MDR phenomenon can be obtained by using geometric optics.
This description is valid when the wavelength of the light used to excite the optical modes is much smaller than the size of the optical cavity. In this geometric view, light coupled into the microsphere (for example using a single mode optical fiber) circles the interior of the sphere through total internal reflection as long as the refractive index of the sphere is larger than that of the surrounding medium. There are many experiments to investigate the effect of angular velocity on the MDR shifts of 60:1 and 10:1 polydimethylsiloxane (PDMS). The opto-electronic setup that the scientists used to excite and monitor the MDR is the same as described in this figure:

Briefly, the output of a distributed feedback (DFB) laser (nominal central wavelength 1.312 μm) was coupled at one end of a single mode optical fiber, while the other end was terminated to a photodiode to monitor the transmission spectrum. The DFB laser was currenttuned to excite the optical resonances. The light was coupled evanescently into the microsphere using a tapered section of a single mode optical fiber. The optical fiber was brought in contact with the resonator using a micro translation stage. Once resonances were observed trough the transmission spectrum, the fiber holder was glued to the disk.

While this design is rotational stage in one axis only but there is a design in 3 axis, this design is rotation Stage provides ±5° uncoupled tilt adjustment in pitch and roll, together with ±10° rotation (yaw) adjustment. 

These adjustments allow optical components and fixtures to be aligned with a plane, and then rotated within that plane.

But we found that this design is not enough because it is only manual and not has enough accuracy so we have been modified this design to increase its accuracy and to be manual and motorized at the same time.