To date,fluorescence imaging systems have all relied on at least one beam splitter(BS)to ensure the separation of excitation light and fluorescence.Here,we reported SiO2=TiO2 multi-layer long pass filter integrated Ga...To date,fluorescence imaging systems have all relied on at least one beam splitter(BS)to ensure the separation of excitation light and fluorescence.Here,we reported SiO2=TiO2 multi-layer long pass filter integrated GaN LED.It is considered as the potential source for imaging systems.Experimental results indicate that the GaN LED shows blue emission peaked at 470.3 nm and can be used to excite dye materials.Integrating with a long pass filter(550 nm),the light source can be used to establish a real-time fluorescence detection for dyes that emit light above 550 nm.More interestingly,with this source,a real-time imaging system with signature words written with the dyes,such as‘NJUPT’,can be converted into CCD images.This work may lead to a new strategy for integrating light sources and BS mirrors to build mini and smart fluorescence imaging systems.展开更多
The development of small-scale self-focusing in a nonlinear Kerr medium after preliminary self-filtering of a laser beam propagating in free space is studied numerically.It is shown that,under definite conditions,due ...The development of small-scale self-focusing in a nonlinear Kerr medium after preliminary self-filtering of a laser beam propagating in free space is studied numerically.It is shown that,under definite conditions,due to self-filtering,filamentation instability(beam splitting into filaments)either occurs at significantly larger values of the B-integral,or does not occur at all.In the latter case,there develops the honeycomb instability revealed in this work.This instability is the formation of a random honeycomb structure in the beam cross-section.It is shown that self-filtering can significantly increase the permissible values of the B-integral,at which the beam quality remains acceptable.展开更多
An injection-seeded single-frequency Q-switched Nd：YAG laser is accomplished by using a phase modulated rampfire technique. A RbTiOPO4（RTP） electro-optic crystal is selected for effective optical path length modula...An injection-seeded single-frequency Q-switched Nd：YAG laser is accomplished by using a phase modulated rampfire technique. A RbTiOPO4（RTP） electro-optic crystal is selected for effective optical path length modulation of the slave self-filtering unstable resonator. This single-frequency laser is capable of producing 50 m J pulse energy at 1 Hz repetition rate with a pulse width of 16 ns. The standard deviation of laser pulse intensity for consecutive 100 shots from the mean pulse intensity is less than 1.05%. A spectral linewidth of less than 0.5 pm with a frequency jitter of about 14 fm over30 min is obtained.展开更多
All space-time coupling effects arising in an asymmetric optical compressor consisting of two non-identical pairs of diffraction gratings are described analytically.In each pair,the gratings are identical and parallel...All space-time coupling effects arising in an asymmetric optical compressor consisting of two non-identical pairs of diffraction gratings are described analytically.In each pair,the gratings are identical and parallel to each other,whereas the distance between the gratings,the groove density and the angle of incidence are different in different pairs.It is shown that the compressor asymmetry does not affect the far-field fluence and on-axis focal intensity.The main distinctive feature of the asymmetric compressor is spatial noise lagging behind or overtaking the main pulse in proportion to the transverse wave vector.This results in a degraded contrast but reduces beam fluence fluctuations at the compressor output.Exact expressions are obtained for the spectrum of fluence fluctuations and fluence root mean square that depends only on one parameter characterizing compressor asymmetry.The efficiency of small-scale self-focusing suppression at subsequent pulse post-compression is estimated.展开更多
基金supported by the National Natural Science Foundation of China(Nos.62004103,61827804,and 62005130)the Natural Science Foundation of Jiangsu Province(Nos.BK20200755,BK20210593,and BK20200743)+4 种基金the“111”Project(No.D17018)the NUPTSF(No.NY220118)the STCSM(No.SKLSFO2020-04)the Foundation of Jiangsu Provincial Double-Innovation Doctor Program(No.30644)the Start-up Fund(Nos.NY219147 and NY220181).
文摘To date,fluorescence imaging systems have all relied on at least one beam splitter(BS)to ensure the separation of excitation light and fluorescence.Here,we reported SiO2=TiO2 multi-layer long pass filter integrated GaN LED.It is considered as the potential source for imaging systems.Experimental results indicate that the GaN LED shows blue emission peaked at 470.3 nm and can be used to excite dye materials.Integrating with a long pass filter(550 nm),the light source can be used to establish a real-time fluorescence detection for dyes that emit light above 550 nm.More interestingly,with this source,a real-time imaging system with signature words written with the dyes,such as‘NJUPT’,can be converted into CCD images.This work may lead to a new strategy for integrating light sources and BS mirrors to build mini and smart fluorescence imaging systems.
基金supported by the Ministry of Science and Higher Education of the Russian Federation(075-15-2020906,Center of Excellence‘Center of Photonics’)。
文摘The development of small-scale self-focusing in a nonlinear Kerr medium after preliminary self-filtering of a laser beam propagating in free space is studied numerically.It is shown that,under definite conditions,due to self-filtering,filamentation instability(beam splitting into filaments)either occurs at significantly larger values of the B-integral,or does not occur at all.In the latter case,there develops the honeycomb instability revealed in this work.This instability is the formation of a random honeycomb structure in the beam cross-section.It is shown that self-filtering can significantly increase the permissible values of the B-integral,at which the beam quality remains acceptable.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2017YFB1104500 and 2016YFB0701000)
文摘An injection-seeded single-frequency Q-switched Nd：YAG laser is accomplished by using a phase modulated rampfire technique. A RbTiOPO4（RTP） electro-optic crystal is selected for effective optical path length modulation of the slave self-filtering unstable resonator. This single-frequency laser is capable of producing 50 m J pulse energy at 1 Hz repetition rate with a pulse width of 16 ns. The standard deviation of laser pulse intensity for consecutive 100 shots from the mean pulse intensity is less than 1.05%. A spectral linewidth of less than 0.5 pm with a frequency jitter of about 14 fm over30 min is obtained.
基金supported by the Ministry of Science and Higher Education of the Russian Federation(075-15-2020-906,Center of Excellence‘Center of Photonics’).
文摘All space-time coupling effects arising in an asymmetric optical compressor consisting of two non-identical pairs of diffraction gratings are described analytically.In each pair,the gratings are identical and parallel to each other,whereas the distance between the gratings,the groove density and the angle of incidence are different in different pairs.It is shown that the compressor asymmetry does not affect the far-field fluence and on-axis focal intensity.The main distinctive feature of the asymmetric compressor is spatial noise lagging behind or overtaking the main pulse in proportion to the transverse wave vector.This results in a degraded contrast but reduces beam fluence fluctuations at the compressor output.Exact expressions are obtained for the spectrum of fluence fluctuations and fluence root mean square that depends only on one parameter characterizing compressor asymmetry.The efficiency of small-scale self-focusing suppression at subsequent pulse post-compression is estimated.
