We have developed an Atomic Force / Photon Scanning Tunneling Microscope (AF/PSTM) to eliminate the optical false image caused by topography of sample in PSTM. The key element of this system is bi-functional bent optical fiber probe, which can both be an optical cantilever and a device to collect the evanescent wave in near field of samples. In this paper, we derived a method to fabricate the bi-functional bent optical probes of AF/PSTM using communication optical fibers. The heated pulling combined with chemical etching method is proposed and developed. Fiber probes with an apex having a diameter smaller than 100nm could be produced with a controlled cone angles vary from 40 to 90 degrees. The back of the probe is finally coated with aluminum to enhance the reflection and with SiO2 to prevent Al film from oxidating in the atmosphere. This method is straightforward and fast. Using probes made with this method, the images of biology samples are obtained and the image separation is realized.
Proc. SPIE. 5630, Optics in Health Care and Biomedical Optics: Diagnostics and Treatment II
KEYWORDS: Nanostructures, Refractive index, Biomedical optics, Statistical analysis, Atomic force microscopy, Biology, Near field scanning optical microscopy, Biological research, Scanning probe microscopy, Near field optics
As an analysis tool, SPM has been broadly used in biomedicine in recent years, such as AFM and SNOM; they are effective instruments in detecting life nanostructures at atomic level. Atomic force and photon scanning tunneling microscope (AF/PSTM) is one of member of SPM, it can be used to obtain sample’ optical and atomic fore images at once scanning, these images include the transmissivity image, reflection index image and topography image. This report mainly introduces the application of AF/PSTM in red blood membrane and the effect of different sample dealt with processes on the experiment result. The materials for preparing red cells membrane samples are anticoagulant blood, isotonic phosphatic buffer solution (PBS) and new two times distilled water. The images of AF/PSTM give real expression to the biology samples’ fact despite of different sample dealt with processes, which prove that AF/PSTM suits to biology sample imaging. At the same time, the optical images and the topography image of AF/PSTM of the same sample are complementary with each other; this will make AF/PSTM a facile tool to analysis biologic samples’ nanostructure. As another sample, this paper gives the application of AF/PSTM in immunoassay, the result shows that AF/PSTM is suit to analysis biologic sample, and it will become a new tool for biomedicine test.
KEYWORDS: Refractive index, Patents, Magnesium fluoride, Glasses, Photography, Atomic force microscopy, Near field scanning optical microscopy, Scanning tunneling microscopy, Photonic microstructures, Near field optics
According to author's Chinese invented patent ZL96 I II 979.9 named "The method of separating image of AF/PSTM (atom force and photon scanning tunneling microscope)", the first system ofAF/PSTM has been developed. Its principle, photograph, block diagram and some images ofan examination sample have been given in this paper. There are three advantages of this system: (1) AF/PSTM can eliminate the optical false image which caused by topography of sample in PSTM; (2) The optical images and topographic image of sample are separated with this AF/PSTM; (3) From once scanning imaging two optical images (refractive index image and transmissivity image) and two AFM images (topography image and phase or grads oftopography image) can be obtained.
Our research group has recently developed a new type scanning probe microscope —AF/ PSTM. Using this setup, the optical false image caused by the inclination of sample surface can be eliminated; the optical image and the topography image are separated; and also two optical images (refractive index image, transmittivity image) and two AFM images (topography image, phase image) are obtained during one scanning. As a primary biologic application, this setup is engaged in the imaging of some biologic samples. The primary images ofthese biologic samples are obtained. Due to the advantage of AFIPSTM, four images can be acquired at the same time during one scanning. Consequently more information ofsample is given by comparing these images. This work shows that the AF/PSTM may be improved to be a useful tool in biology research.