Nearfield Microscope (NEFUS)

Near-field microscopy (NEFUS), a static test stand, is used to test the near-field optics such as solid immersion lens (SIL) and Aperture-SIL (APSIL). The basic layout of the microscope includes a Laser source, a light modulator, relay tubes, an Olympus IX70 microscope, and a detector.  The details of the experimental setup are shown in Figure 1. As shown in Figure1, linearly polarized laser light is focused into the APSIL by an objective lens in the microscope. The half-wave plate is used to change the polarization direction with respect to the tracks of the recording medium. The APSIL is mounted on a thin metal plate that can be positioned by a picomotor. Spacing between the probe and the recording medium is controlled to ~ 40 nm by the fine movement of the picometer along the z direction, as well as indication from a strain gauge. High precision spot/aperture alignment is achieved by fine movement of the picomotor along x and y directions. The microscope slide holding the recording medium is translated along x or y directions by a piezo actuator, so the small light spot formed by the aperture probe can record and readout a series of data marks on the medium. The slide speed is 12 mm/sec, which is slow enough to neglect the air disturbance between the probe and medium. The reflected light off the medium is then collected by the objective lens and directed into the detector at the pupil plane conjugate to the stop by the action of the relay lens. The detector has two channels that provide sum and difference signals. The acoustic optical modulator is used to modulate the laser light at certain amplitude and pulse width. All the hardware derives in the experiment are controlled by a computer.

                                                 Figure 1

Papers co-written with Tom Milster:

High-performance readout and recording by a combination aperature.pdf

Other News

Friday, September 20th, 2002:

My wife Sandy has been checked by the Doctor here. The results show the baby is healthy and the weight increases to 4.5 lbs. I have a big release when knowing this result. Sandy has been 36 weeks in pregnancy, so the baby is expected to come out in next four weeks. I will enjoy to be a father for a newborn again (less sleep and dirty dippers).


My updated contact information is below:

Phone:  (H) 518-373-2789
(O) 518-387-5287

Email:   tangg@crd.ge.com


 

Tuesday, October 1st, 2002:

Dear all:

My baby Brittny came to the world on 9/28, two weeks earlier than the due day. She is healthy and weighs 5 lb. and 4 oz. Sandy found her water broke on 9/27. She tried to be in labor but still ended up with a cesarean section. She is recovering now.


Gordon