Standing-Wave
Total Internal Reflection Microscopy (SW-TIRM)
Investigators:
Euiheon Chung, Peter So
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Light
microscopy is widely used in biomedical research to study living
biological systems. A major limitation of optical imaging is its
inability to resolve objects with separation below several hundred
nanometers. Even though there are several scanning-probe methods
with higher resolution such as atomic force microscopy, there is
significant resolution degradation in soft biological specimens
and this method is inherently slow due to point-by-point scanning.
Thus there is a need to develop a wide-field optical imaging method
with below 100nm resolution.
|
The use of Standing
evanescent wave imaging in a total internal reflection geometry
have shown that lateral resolution better than 1/6 of excitation
wavelength can be achieved. The enhanced image results from the
high-spatial frequency modulation to the conventional point-spread
function.
Figure 1: 3D point-spread
function of SW-TIRM which has narrower PSF in the direction of
standing wave.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Figure 2: A schematic
diagram of SW-TIRM which shows the basic idea of generating standing
evanescent wave and imaging.
If this development
is successful, the technology should have interesting applications
in cell biology, single molecular level detection, protein studies
and the examination of pathological specimens.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
1
- So P.T.C. et al. (2001) Resolution enhancement in standing-wave
total internal reflection microscopy: a point-spread function engineering
approach. J. Opt. Soc. Am.A, 18, No.11: 2833-2845.
2 - Cragg G.E. et al. (2000) Lateral resolution enhancement
with standing evanescent waves. Optics Letters, 25:
46-48.
|