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We demonstrate vertical cross-sectional (XZ-plane) images of near-infrared (NIR) fluorescence with a handheld dual axes confocal endomicroscope that reveals specific binding of a Cy5.5-labeled peptide to pre-malignant colonic mucosa. This view is perpendicular to the tissue surface, and is similar to that used by pathologists. The scan head is 10 mm in outer diameter (OD), and integrates a one dimensional (1-D) microelectromechanical systems (MEMS) X-axis scanner and a bulky lead zirconate titanate (PZT) based Z-axis actuator. The microscope images in a raster-scanning pattern with a ±6 degrees (mechanical) scan angle at ~3 kHz in the X-axis (fast) and up to 10 Hz (0–400 μm) in the Z-axis (slow). Vertical cross-sectional fluorescence images are collected with a transverse and axial resolution of 4 and 5 μm, respectively, over a field-of-view of 800 μm (width) × 400 μm (depth). NIR vertical cross-sectional fluorescence images of fresh mouse colonic mucosa demonstrate histology-like imaging performance with this miniature instrument.

Step height and line-width are two key parameters in the metrology of micro-electronic masks. A novel common-path heterodyne interferometric confocal measuring system is presented to measure the step height of masks. It combines both the methods of heterodyne interferometry and confocal microscopy. The resolution is 0.01 nm and the measurement range is around 8 µm. The procedure is direct by the integration of the measurement of intensity and phase, hereby faster than a normal scanning microscope. For the line-width measurement of masks, a polarization heterodyne interferometric confocal microscope is proposed, which combines a polarization interferometer with a confocal microscope. An ideal beam spot is obtained and precise focus is realized by using the confocal technique. The phase shifts of the two orthogonal polarization beams differ from each other when they are reflected at the edge of a sample. The experimental results show that the uncertainty of line-width measurement is 21 nm. Both of the systems satisfy the common-path principle, so as to get high ability of resistance to environment disturbances.

Plane mirror interferometers are usually utilized to nano-position large-range scanning stage in microelectronic mask measurement systems. To avoid Abbe-error the centerline of measurement light beams of X Y Z should be intersected at the upper surface of the mask. But the different thickness of masks can also lead to Abbe errors. In this paper a novel plane mirror interferometer is designed, in which the measurement centerline can be accurately adjusted in coincidence with the upper surface of the mask according to their different thickness. The Abbe arm of this interferometer can be decreased to zero and the Abbe-error is avoided completely. The range of different thickness that can be adapted in this interferometer is ±3 mm. In this paper a quadrant photoelectric cell adapter is used to measure the centerline of the measurement light beams and the uncertainty of this method is better than 0.02 mm, which can meet the needs of nano-positioning of microelectronic mask measurement.

A novel roll angle interferometer using a transverse Zeeman laser (TZL) is proposed in this paper. The orthogonally linearly-polarized light from TZL is changed to be slightly elliptically-polarized light by a quarter wave plate (QWP) when the principal axis of the QWP is at a small angle with the basis of the direction of polarization. The beam then passes through a half wave plate (HWP) that is employed as a sensor. After that it is reflected by a right angle prism (RAP) and returns to the HWP again. Owing to the reasonable transformation of coordinates by the prism, the change of direction of polarization is accumulated twice when the beam passes forward and back through the HWP. Theoretical analysis and experimental results show that the sensitivity of roll measurement can reach sub-second and be improved four times than that we had reported. This system of implementing roll measurement takes the advantage of compactness, stable performance, low cost and robust to the environment disturbance.

A diode-pumped solid state laser is used to deliver excitation at O ex = 671 nm. The beam is expanded by a pair of relay lenses (f 1 = 30 and f 2 = 50 mm) to 3 mm diameter, filling the aperture of a fluid light cable that is coupled to a Hopkins® II rigid endoscope. Near-infrared fluorescence images are collected by the endoscope and transmitted by another set of relay lenses onto a CCD detector that has dimensions of 8.7x6.9 mm 2 (1388x1040 pixels). A zoom lens system (F#1.6-16 aperture) with a tunable focal length (20-100 mm) magnifies the image to fill the dimensions of the CCD. A band pass filter allows fluorescence with spectral range O em = 696 to 736 nm to be collected. The system achieves a resolution of 9.8 P m and field-of-view of 3.6 mm at a dist ance of 2.5 mm between the distal end of the endoscope and the tissue. Images are collected at a ra te of 10 frames per second. A filter wheel is incorporated into the handle of the instrument housing to rapidly switch between reflectance and fluorescence images. Cy5.5-labeled peptides were delivered through the 1 mm diameter instrument channel in the endoscope. Near-infrared fluorescence images demonstrated specific peptide binding to spontaneous adenomas that developed beginning at 2 months of age in a genetically-engineered mouse with mutation of one allele in the APC gene. This integrated methodology represents a powerful tool th at can achieve real time detection of disease in the colon and other hollow organs. Keywords : endoscope, CCD, imaging, fluorescence, ne ar-infrared, real-time, colon, cancer

A novel transmitted-light differential interference contrast (DIC) system is used for nondestructive measurement of the refractive-index profile (RIP) of an optical fiber. By means of this system the phase of a measured light beam can be modulated with an analyzer, and the phase distribution of a fiber is obtained by calculation of the various interference patterns. The measurement theory and structure and some typical applications of this system are demonstrated. The results of measuring RIPs in graded-index fiber are presented. Both the experimental results and theoretical analysis show that the system takes the advantage of high index resolution and of sufficient measurement accuracy for measuring the refractive index of the optical fiber. The system has strong ability to overcome environmental disturbance because of its common-path design. Moreover, one can use the system to measure the RIP along the fiber axis and acquire an image of the three-dimensional RIP of the fiber.

A novel instrument, the dual-frequency interferometric confocal microscope (DICM), which facilitates the measurement of step features, is investigated. It combines the advantages of the high resolution (subnanometer) of heterodyne interferometry and the relatively large measurement range (approximately 5 microm) of confocal microscopy. The axial response curves of the confocal microscopy system are compared in experiments in which microscopic objects with various numerical apertures and magnifications are used. The results prove that the variation in light intensity is enough to permit discrimination of different orders of interference fringes. The DICM has been successfully utilized to measure the step height of a standard mask, and the experimental results agree well with those measured by scanning probe microscopes. The results also show that the system has good repeatability, with a maximum deviation of 5 nm.