Research Of Improving Lateral Resolution Of Confocal Microscopy With Spatiotemporal Modulation

Confocal microscope has been widely applied in almost all walks of science andtechnology such as industrial and biological imaging fields thanks to its distinctive axialoptical sectioning property. However, its lateral resolution is still restricted within anorder of wavelength of the light source due to diffraction, while its axial resolution hasbeen to an order of nanometer, as a result of which, this great unbalance between lateraland axial resolution has affected the whole imaging ability in three dimension.Therefore, it is increasingly essential to improve the lateral resolution, with the modernindustrial and biological tests stepping into the age of nanometer.This subject, research of improving lateral resolution of confocal microscopy withspatiotemperal modulation, aims to break the diffraction barrier for improving thelateral resolution of confocal microscope. To begin with the principle of Laue-Lukoszinvariant theory of number N of degrees of freedom, on the account of the theories ofspatiotemporal modulation with gratings and confocal microscopy measurement, thispaper brings the principle of spatiotemporal modulation with gratings into a confocalmicroscope to obtain lateral super-resolution in the confocal microscope.The paper is organized as follows:Firstly, the research is started in super-resolution approach through spatiotemporalmodulation with gratings. From the point of view of Laue-Lukosz invariant theory, thefoundational theory of4-F optical system through spatiotemporal modulation withmoving gratings has been studied and it has been proved that the bandwidth of spatialfrequency domain of an optical system is increased by spatiotemporal modulationwithout enlarging the numeral aperture, and the influence of grating parameters on thecoherence transfer function of the optical system is compared and analyzed.Secondly, the research is set up in super-resolution confocal microscopy approachthrough spatiotemporal modulation with gratings. After introducing the spatiotemporalmodulation method into a confocal microscope, the two-dimensional coherent imageformula in the real domain and the two-dimensional coherence transfer function in thefrequency domain have been deduced on the condition of coherent illumination and nodefocus distance, with the influence of grating parameters on the lateral intensityresponse characteristics analyzed and compared, taking account of threesuper-resolution characteristic quantities.Thirdly, the imaging principle of confocal microscopy through spatiotemporalmodulation with fixed grating is studied. Aiming to overcome the drawback ofsuper-resolution system with moving grating above, confocal microscope through spatiotemporal modulation with fixed grating is put forward and the optical fielddistribution has been deduced and analyzed by simulation in the real and frequencydomains respectively.Fourthly, the imaging principle of confocal microscopy through spatiotemporalmodulation with acoustic grating is researched. Confocal microscopy throughspatiotemporal modulation with acoustic grating is developed, and its theory andsimulation model is set up on the condition of coherent illumination system as well asincoherent imaging system, with the merits and demerits of the confocal microscopythrough spatiotemporal modulation based on moving gratings, fixed grating andacoustic grating compared and analyzed on the terms of the real and frequency domainsas well as the accomplishing means.Finally, a synchronous laser scanning system with an acoustic optical modulatorand a set of two-dimensional scanning mirrors is designed and the experiment platformis set up to obtain the two-dimensional lateral imaging results of confocal microscopethrough spatiotemporal modulation with acoustic grating and conventional confocalmicroscope, with experiments proving the correctness of lateral super-resolution theoryof confocal microscopy through spatiotemporal modulation.