Simultaneous control on the intensity and phase profile of laser beam with Monge-Ampère equation method

2014 ◽  
Author(s):  
Yaqin Zhang ◽  
Rengmao Wu ◽  
Zhenrong Zheng ◽  
Haifeng Li ◽  
Xu Liu
Keyword(s):  
Laser Beam ◽  
Equation Method ◽  
Simultaneous Control ◽  
Phase Profile ◽  
Monge Ampere

Double freeform surfaces design for laser beam shaping with Monge–Ampère equation method

2014 ◽  
Vol 331 ◽  
pp. 297-305 ◽  
Author(s):  
Yaqin Zhang ◽  
Rengmao Wu ◽  
Peng Liu ◽  
Zhenrong Zheng ◽  
Haifeng Li ◽  
...  
Keyword(s):  
Laser Beam ◽  
Beam Shaping ◽  
Equation Method ◽  
Laser Beam Shaping ◽  
Freeform Surfaces ◽  
Monge Ampere

scholarly journals Metrology of a Focusing Capillary Using Optical Ptychography

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6462
Author(s):  
Xiaojing Huang ◽  
Evgeny Nazaretski ◽  
Weihe Xu ◽  
Dean Hidas ◽  
Mark Cordier ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Laser Beam ◽  
Gaussian Distribution ◽  
Capillary Surface ◽  
Functional Surfaces ◽  
Phase Profile ◽  
Reflective Optics ◽  
Focusing Property ◽  
Focused Beam ◽  
Quantitative Tool

The focusing property of an ellipsoidal monocapillary has been characterized using the ptychography method with a 405 nm laser beam. The recovered wavefront gives a 12.5×10.4μm2 focus. The reconstructed phase profile of the focused beam can be used to estimate the height error of the capillary surface. The obtained height error shows a Gaussian distribution with a standard deviation of 1.3 μm. This approach can be used as a quantitative tool for evaluating the inner functional surfaces of reflective optics, complementary to conventional metrology methods.

Designing two freeform surfaces with Monge–Ampère equation method for point-like sources

2018 ◽  
Author(s):  
Rengmao Wu ◽  
Zhenrong Zheng ◽  
Shengqian Chang ◽  
Zhanghao Ding
Keyword(s):  
Equation Method ◽  
Freeform Surfaces ◽  
Monge Ampere

scholarly journals Influence of the characteristics of a light source and target on the Monge–Ampére equation method in freeform optics design

2014 ◽  
Vol 39 (3) ◽  
pp. 634 ◽  
Author(s):  
Rengmao Wu ◽  
Pablo Benítez ◽  
Yaqin Zhang ◽  
Juan C. Miñano
Keyword(s):  
Light Source ◽  
Equation Method ◽  
Freeform Optics ◽  
Monge Ampere ◽  
Optics Design

scholarly journals Initial design with L^2 Monge-Kantorovich theory for the Monge–Ampère equation method in freeform surface illumination design

2014 ◽  
Vol 22 (13) ◽  
pp. 16161 ◽  
Author(s):  
Rengmao Wu ◽  
Yaqin Zhang ◽  
Mohamed M. Sulman ◽  
Zhenrong Zheng ◽  
Pablo Benítez ◽  
...  
Keyword(s):  
Equation Method ◽  
Freeform Surface ◽  
Illumination Design ◽  
Initial Design ◽  
Monge Ampere

scholarly journals Quadratic Meta-Reflectors Made of HfO2 Nanopillars with a Large Field of View at Infrared Wavelengths

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1148 ◽  
Author(s):  
Feng Tang ◽  
Xin Ye ◽  
Qingzhi Li ◽  
Hailiang Li ◽  
Haichao Yu ◽  
...  
Keyword(s):  
Laser Beam ◽  
Focal Depth ◽  
Field Of View ◽  
Optical Systems ◽  
Large Field ◽  
Quadratic Phase ◽  
Phase Profile ◽  
Potential Applications ◽  
Infrared Wavelengths ◽  
Phase Amplitude

Metasurfaces, being composed of subwavelength nanostructures, can achieve peculiar optical manipulations of phase, amplitude, etc. A large field of view (FOV) is always one of the most desirable characteristics of optical systems. In this study, metasurface-based quadratic reflectors (i.e., meta-reflectors) made of HfO2 nanopillars are investigated to realize a large FOV at infrared wavelengths. First, the geometrical dependence of HfO2 nanopillars’ phase difference is analyzed to show the general principles of designing infrared HfO2 metasurfaces. Then, two meta-reflectors with a quadratic phase profile are investigated to show their large FOV, subwavelength resolution, and long focal depth. Furthermore, the two quadratic reflectors also show a large FOV when deflecting a laser beam with a deflecting-angle range of approximately ±80°. This study presents a flat optical metamaterial with a large FOV for imaging and deflecting, which can greatly simplify the optical–mechanical complexity of infrared systems, particularly with potential applications in high-power optical systems.

Two-photon excitation microscopy in cellular biophysics

1995 ◽  
Vol 53 ◽  
pp. 62-63
Author(s):  
David W. Piston ◽  
Brian D. Bennett ◽  
Robert G. Summers
Keyword(s):  
Confocal Microscopy ◽  
Laser Beam ◽  
Duty Cycle ◽  
Excited Electronic State ◽  
Input Power ◽  
Two Photon ◽  
Simultaneous Absorption ◽  
Photon Excitation ◽  
Very High ◽  
Two Photon Excitation

Two-photon excitation microscopy (TPEM) provides attractive advantages over confocal microscopy for three-dimensionally resolved fluorescence imaging and photochemistry. Two-photon excitation arises from the simultaneous absorption of two photons in a single quantitized event whose probability is proportional to the square of the instantaneous intensity. For example, two red photons can cause the transition to an excited electronic state normally reached by absorption in the ultraviolet. In practice, two-photon excitation is made possible by the very high local instantaneous intensity provided by a combination of diffraction-limited focusing of a single laser beam in the microscope and the temporal concentration of 100 femtosecond pulses generated by a mode-locked laser. Resultant peak excitation intensities are 106 times greater than the CW intensities used in confocal microscopy, but the pulse duty cycle of 10-5 maintains the average input power on the order of 10 mW, only slightly greater than the power normally used in confocal microscopy.

The atomic-force microscope and its future in biology

1993 ◽  
Vol 51 ◽  
pp. 704-705
Author(s):  
Jean-Paul Revel
Keyword(s):  
Silicon Nitride ◽  
Laser Beam ◽  
Atomic Force Microscope ◽  
Scanning Tunneling Microscope ◽  
Point Of View ◽  
Scanning Tunneling ◽  
Close Relative ◽  
Tunneling Microscope ◽  
Atomic Force ◽  
Sharp Point

The last few years have been marked by a series of remarkable developments in microscopy. Perhaps the most amazing of these is the growth of microscopies which use devices where the place of the lens has been taken by probes, which record information about the sample and display it in a spatial from the point of view of the context. From the point of view of the biologist one of the most promising of these microscopies without lenses is the scanned force microscope, aka atomic force microscope.This instrument was invented by Binnig, Quate and Gerber and is a close relative of the scanning tunneling microscope. Today's AFMs consist of a cantilever which bears a sharp point at its end. Often this is a silicon nitride pyramid, but there are many variations, the object of which is to make the tip sharper. A laser beam is directed at the back of the cantilever and is reflected into a split, or quadrant photodiode.

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