OptoFluidic Adaptive Optics (OFAO)

• Applicant: Professor Dr. Caglar Ataman
• Subject Area: Microsystems ; Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering ; Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 2016 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 274458620

• Final Report Year: 2019

Final Report Abstract

A wide variety of life science microscopy methods, both in confocal and full-field modalities, have adapted adaptive optics (AO) for the compensation of sample and/or system induced phase aberrations, leading to enhanced resolution as well as contrast, particularly for deep tissue imaging. However, widespread adoption AO microscopy is severely hindered by the prohibitive cost and complexity of conventional methods, in particular by the limitations imposed by reflective wavefront modulation using deformable mirrors. Optofluidic Adaptive Optics (OFAO) aimed to develop innovative hardware and software to address this crucial problem, and ultimately pave the way for objective-integrated AO microscopy. The core innovation of OFAO is a highly miniaturized two-dimensionally actuated optofluidic transmissive wavefront modulator. The device comprises a cavity sealed by a flexible polymeric membrane on one side, and a rigid transparent substrate on the other. An array of 37 individually addressable transparent thin-film ITO electrodes are patterned on to the borosilicate substrate, covering the 10 mm diameter optical aperture. Depending on the requirements of the target application, the total electrode number and their spatial distribution (e.g. hexagonal or keystone) are easily adaptable. To render the actuators optically passive, the entire structure is constructed from transparent materials. Since the actuation is electrostatic, the device behavior is strongly linear and essentially hysteresis-free. Compared to its counterparts, the optofluidic phase modulator uniquely combines: • Transmissive/refractive operation, • Wavelength and polarization independent, high-efficiency correction,• High-fidelity correction including spherical aberration,• Ultra-miniaturized dimensions, • Linear and hysteresis-free operation,• Cost-efficient batch manufacturing. To exploit these unique combination of features to the fullest, OFAO has devised a new optimizationbased open-loop control scheme tailored particularly for the modulator. Combined with customdeveloped driving electronics, it demonstrated real-time and accurate reproduction of target wavefront shapes. Very high fidelity reconstruction of Zernike modes up to the 5th radial order is demonstrated. In its final stage, OFAO also realized an in-line adaptive optics fluorescence microscope featuring the optofluidic refractive phase modulator at its pupil plane to correct for system and sample induced optical aberrations. To eliminate the need for a wavefront sensor, a modal decomposition based sensorless wavefront estimation algorithm was employed. Using this microscope, effective image improvement through the correction of both known/test and arbitrary aberrations have been demonstrated on artificial as well as biological samples. Building upon the prior expertise of both its PI and the laboratory within which it was carried out, OFAO has yielded a complete and innovative set of hardware and software tools for adaptive microscopy that can also be adapted to wide range of beam shaping applications.

Publications

• “Piezoelectric pvdf actuated, lightweight deformable thin mirror for adaptive optics,” in 2016 International Conference on Optical MEMS and Nanophotonics (OMN), pp. 1–2, IEEE, 2016
  Banerjee, Kaustubh; Rajaeipour, Pouya; Ataman, Caglar & Zappe, Hans
  
• “A highly-miniaturized optofluidic refractive adaptive optics system,” in Adaptive Optics: Analysis, Methods & Systems, pp. OW2J–6, Optical Society of America, 2018
  Banerjee, Kaustubh; Rajaeipour, Pouya; Ataman, Çağlar & Zappe, Hans
  
• “A low-cost 25-actuator electrostatic deformable mirror with polyimide membrane for adaptive optics microscopy,” in MOEMS and Miniaturized Systems XVII, vol. 10545, p. 105450G, International Society for Optics and Photonics, 2018
  Banerjee, Kaustubh; Rajaeipour, Pouya; Ataman, Caglar & Zappe, Hans
  
• “An optofiuidic refractive phase modulator with an electrostatic 2d actuator array,” in 2018 International Conference on Optical MEMS and Nanophotonics (OMN), pp. 1–2, IEEE, 2018
  Banerjee, Kaustubh; Rajaeipour, Pouya; Ataman, Caglar & Zappe, Hans
  
• “Optofluidic adaptive optics,” Applied optics, vol. 57, no. 22, pp. 6338–6344, 2018
  Banerjee, Kaustubh; Rajaeipour, Pouya; Ataman, Çağlar & Zappe, Hans
  
• “A 37-actuator polyimide deformable mirror with electrostatic actuation for adaptive optics microscopy,” Journal of Micromechanics and Microengineering, vol. 29, no. 8, p. 085005, 2019
  Banerjee, Kaustubh; Rajaeipour, Pouya; Zappe, Hans & Ataman, Çağlar
  
• “Compact all in-line adaptive optics fluorescence microscope using an optofluidic phase modulator,” in Optical MEMS and Nanopotonics, Institute of Electrical and Electronics Engineers, 2019
  Dorn, Alex; Rajaeipour, Pouya; Banerjee, Kaustubh; Zappe, Hans & Ataman, Caglar
  
• “Optimization-based open-loop control of phase modulators for adaptive optics,” in Adaptive Optics and Wavefront Control for Biological Systems V, vol. 10886, p. 108861A, International Society for Optics and Photonics, 2019
  Rajaeipour, Pouya; Banerjee, Kaustubh; Ataman, Caglar & Zappe, Hans
  
• “Optimization-based real-time open-loop control of an optofluidic refractive phase modulator,” Applied optics, vol. 58, no. 4, pp. 1064–1072, 2019
  Rajaeipour, Pouya; Banerjee, Kaustubh; Zappe, Hans & Ataman, Çağlar
  
• “Refractive opto-fluidic wavefront modulator with electrostatic push-pull actuation,” in Adaptive Optics and Wavefront Control for Biological Systems V, vol. 10886, p. 108860D, International Society for Optics and Photonics, 2019
  Banerjee, Kaustubh; Rajaeipour, Pouya; Ataman, Caglar & Zappe, Hans