Design of high-performance adaptive objective lens with large optical depth scanning range for ultrabroad near infrared microscopic imaging.

We report on the theory and design of adaptive objective lens for ultra broadband near infrared light imaging with large dynamic optical depth scanning range by using an embedded tunable lens, which can find wide applications in deep tissue biomedical imaging systems, such as confocal microscope, optical coherence tomography (OCT), two-photon microscopy, etc., both in vivo and ex vivo. This design is based on, but not limited to, a home-made prototype of liquid-filled membrane lens with a clear aperture of 8mm and the thickness of 2.55mm ~3.18mm. It is beneficial to have an adaptive objective lens which allows an extended depth scanning range larger than the focal length zoom range, since this will keep the magnification of the whole system, numerical aperture (NA), field of view (FOV), and resolution more consistent. To achieve this goal, a systematic theory is presented, for the first time to our acknowledgment, by inserting the varifocal lens in between a front and a back solid lens group. The designed objective has a compact size (10mm-diameter and 15mm-length), ultrabroad working bandwidth (760nm - 920nm), a large depth scanning range (7.36mm in air) - 1.533 times of focal length zoom range (4.8mm in air), and a FOV around 1mm × 1mm. Diffraction-limited performance can be achieved within this ultrabroad bandwidth through all the scanning depth (the resolution is 2.22 μm - 2.81 μm, calculated at the wavelength of 800nm with the NA of 0.214 - 0.171). The chromatic focal shift value is within the depth of focus (field). The chromatic difference in distortion is nearly zero and the maximum distortion is less than 0.05%.

[1]  Y. Lo,et al.  Miniaturized universal imaging device using fluidic lens. , 2008, Optics letters.

[2]  J. Curcio,et al.  Near infrared absorption spectrum of liquid water , 1951 .

[3]  Pietro Valdastri,et al.  An integrated vision system with autofocus for wireless capsular endoscopy , 2009 .

[4]  Li Guoqiang,et al.  Adaptive Lens. , 2010, Progress in optics.

[5]  A. Fercher,et al.  In vivo optical coherence tomography. , 1993, American journal of ophthalmology.

[6]  B. J. Feenstra,et al.  Video-speed electronic paper based on electrowetting , 2003, Nature.

[7]  Nasser N Peyghambarian,et al.  High-efficiency switchable flat diffractive ophthalmic lens with three-layer electrode pattern and two-layer via structures , 2007 .

[8]  Yi-Chin Fang,et al.  A study of optical design and optimization of zoom optics with liquid lenses through modified genetic algorithm. , 2011, Optics express.

[9]  S. Kuiper,et al.  Variable-focus liquid lens for miniature cameras , 2004 .

[10]  Antonin Miks,et al.  Analysis of two-element zoom systems based on variable power lenses. , 2010, Optics express.

[11]  Seung S. Lee,et al.  Focal tunable liquid lens integrated with an electromagnetic actuator , 2007 .

[12]  A. Fercher,et al.  Measurement of intraocular distances by backscattering spectral interferometry , 1995 .

[13]  Shin‐Tson Wu,et al.  Variable-focus liquid lens by changing aperture , 2005 .

[14]  Microelectromechanical-System-Based Variable-Focus Liquid Lens for Capsule Endoscopes , 2009 .

[15]  Yi-Chin Fang,et al.  Miniature lens design and optimization with liquid lens element via genetic algorithm , 2008 .

[16]  J. Fujimoto,et al.  Optical Coherence Tomography , 1991 .

[17]  Guoqiang Li,et al.  Switchable electro-optic diffractive lens with high efficiency for ophthalmic applications. , 2006, Proceedings of the National Academy of Sciences of the United States of America.

[18]  Nabeel A. Riza,et al.  Demonstration of three-dimensional optical imaging using a confocal microscope based on a liquid-crystal electronic lens , 2008 .

[19]  P. Hands,et al.  Tunable planar integrated optical systems , 2006 .

[20]  Supraja Murali,et al.  Three-dimensional adaptive microscopy using embedded liquid lens. , 2009, Optics letters.

[21]  De-Ying Zhang,et al.  Integrated fluidic adaptive zoom lens. , 2004, Optics letters.

[22]  Geunbae Lim,et al.  Variable-focus Liquid Lens Based on a Laterally-integrated Thermopneumatic Actuator , 2012 .

[23]  Yi-Chin Fang,et al.  Optical design and multiobjective optimization of miniature zoom optics with liquid lens element. , 2009, Applied optics.

[24]  P. Ferraro,et al.  Tunable liquid microlens arrays in electrode-less configuration and their accurate characterization by interference microscopy. , 2009, Optics express.