Near infrared light-controlled release of payloads from ultraviolet-sensitive(UV-sensitive) polymer hydrogels or nanocarriers is one of the most promising strategies for biotherapy. Here, we propose the concept of lig...Near infrared light-controlled release of payloads from ultraviolet-sensitive(UV-sensitive) polymer hydrogels or nanocarriers is one of the most promising strategies for biotherapy. Here, we propose the concept of light activation of NaYF_4:20%Yb, 2%Tm nanocrystals(NCs). NaYF_4:20%Yb, 2%Tm NCs are synthesized by a solvothermal method. Effective upconversion luminescence from NaYF_4:20%Yb, 2%Tm NCs excited by a continuous wave(CW) 980 nm laser is obtained. The NaYF_4:20%Yb, 2%Tm NCs are then used as a laser gain medium and sandwiched between Al and quartz reflectors to form laser microcavities. UV and blue upconverted random lasing is obtained from the laser microcavities. Hence, we verify explicitly that the NaYF_4:Yb, Tm NCs support UV and blue upconversion random lasing via a 980 nm nanosecond laser excitation. Our work provides what we believe is a new concept for precision and localized cancer therapy by external light excitation.展开更多
We demonstrate a high power,widely tunable femtosecond MgO-doped periodically poled lithium niobate(MgO:PPLN)optical parametric oscillator(OPO)at 151 MHz,pumped by a Kerr-lens mode-locked Yb:KGW laser.With a maximum p...We demonstrate a high power,widely tunable femtosecond MgO-doped periodically poled lithium niobate(MgO:PPLN)optical parametric oscillator(OPO)at 151 MHz,pumped by a Kerr-lens mode-locked Yb:KGW laser.With a maximum pump power of 7 W,the OPO is capable of delivering as high as 2.2 W of the signal centered around 1500 nm with tunable signal spectrum ranges of 1377 nm-1730 nm at an extraction efficiency of 31.4%,which exhibits a long-term passive power stability better than 0.71%rms over 4 h.The maximum idler bandwidths of 185 nm at 3613 nm are obtained across the idler tuning ranges of 2539 nm-4191 nm.By compensating intracavity dispersion,the signal has the shortest pulse duration of 170 fs at 1428 nm.展开更多
Multilayer dielectric gratings typically remove multiple-grating pillars after picosecond laser irradiation;however,the dynamic formation process of the removal is still unclear.In this study,the damage morphologies o...Multilayer dielectric gratings typically remove multiple-grating pillars after picosecond laser irradiation;however,the dynamic formation process of the removal is still unclear.In this study,the damage morphologies of multilayer dielectric gratings induced by an 8.6-ps laser pulse were closely examined.The damage included the removal of a single grating pillar and consecutive adjacent grating pillars and did not involve the destruction of the internal high-reflection mirror structure.Comparative analysis of the two damage morphological characteristics indicated the removal of adjacent pillars was related to an impact process caused by the eruption of localized materials from the left-hand pillar,exerting impact pressure on its adjacent pillars and eventually resulting in multiple pillar removal.A finite-element strain model was used to calculate the stress distribution of the grating after impact.According to the electric field distribution,the eruptive pressure of the dielectric materials after ionization was also simulated.The results suggest that the eruptive pressure resulted in a stress concentration at the root of the adjacent pillar that was sufficient to cause damage,corresponding to the experimental removal of the adjacent pillar from the root.This study provides further understanding of the laser-induced damage behavior of grating pillars and some insights into reducing the undesirable damage process for practical applications.展开更多
基金Natural Science Foundation of SZU(827-000130)National Natural Science Foundation of China(NSFC)(51502176,61378071)Science and Technology Projects of Shenzhen(JCYJ20150324141711618,JCYJ20160427105041864,JCYJ20170818101651195,JSGG20160429114438287)
文摘Near infrared light-controlled release of payloads from ultraviolet-sensitive(UV-sensitive) polymer hydrogels or nanocarriers is one of the most promising strategies for biotherapy. Here, we propose the concept of light activation of NaYF_4:20%Yb, 2%Tm nanocrystals(NCs). NaYF_4:20%Yb, 2%Tm NCs are synthesized by a solvothermal method. Effective upconversion luminescence from NaYF_4:20%Yb, 2%Tm NCs excited by a continuous wave(CW) 980 nm laser is obtained. The NaYF_4:20%Yb, 2%Tm NCs are then used as a laser gain medium and sandwiched between Al and quartz reflectors to form laser microcavities. UV and blue upconverted random lasing is obtained from the laser microcavities. Hence, we verify explicitly that the NaYF_4:Yb, Tm NCs support UV and blue upconversion random lasing via a 980 nm nanosecond laser excitation. Our work provides what we believe is a new concept for precision and localized cancer therapy by external light excitation.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.62165012 and 61665010)the Key Research and Development Projects in Gansu Province,China(Grant No.21YFIGE300)+4 种基金Gansu Province College Industry Support Plan Project(Grant Nos.2020C-23 and 2022CYZC-59)the Natural Science Foundation of Gansu Province,China(Grant Nos.21JR7RE173 and 20JR5RA494)Qinzhou District Science and Technology Plan Project(Grant No.2021-SHFZG-1442)the Scientific Research Innovation Platform Construction Project of Tianshui Normal University,Gansu Province,China(Grant No.PTJ2022-06)Science and Technology Supporting Program Project of Tianshui City(Grant Nos.2022-FZJHK-8548,2019-FZJHK-9891,and 2020-FZJHK-9757).
文摘We demonstrate a high power,widely tunable femtosecond MgO-doped periodically poled lithium niobate(MgO:PPLN)optical parametric oscillator(OPO)at 151 MHz,pumped by a Kerr-lens mode-locked Yb:KGW laser.With a maximum pump power of 7 W,the OPO is capable of delivering as high as 2.2 W of the signal centered around 1500 nm with tunable signal spectrum ranges of 1377 nm-1730 nm at an extraction efficiency of 31.4%,which exhibits a long-term passive power stability better than 0.71%rms over 4 h.The maximum idler bandwidths of 185 nm at 3613 nm are obtained across the idler tuning ranges of 2539 nm-4191 nm.By compensating intracavity dispersion,the signal has the shortest pulse duration of 170 fs at 1428 nm.
基金supported by the National Key R&D Program of China(2018YFE0115900)the Key Foreign Cooperation Projects of Bureau of International Cooperation of Chinese Academy of Sciences(181231KYSB20210001).
文摘Multilayer dielectric gratings typically remove multiple-grating pillars after picosecond laser irradiation;however,the dynamic formation process of the removal is still unclear.In this study,the damage morphologies of multilayer dielectric gratings induced by an 8.6-ps laser pulse were closely examined.The damage included the removal of a single grating pillar and consecutive adjacent grating pillars and did not involve the destruction of the internal high-reflection mirror structure.Comparative analysis of the two damage morphological characteristics indicated the removal of adjacent pillars was related to an impact process caused by the eruption of localized materials from the left-hand pillar,exerting impact pressure on its adjacent pillars and eventually resulting in multiple pillar removal.A finite-element strain model was used to calculate the stress distribution of the grating after impact.According to the electric field distribution,the eruptive pressure of the dielectric materials after ionization was also simulated.The results suggest that the eruptive pressure resulted in a stress concentration at the root of the adjacent pillar that was sufficient to cause damage,corresponding to the experimental removal of the adjacent pillar from the root.This study provides further understanding of the laser-induced damage behavior of grating pillars and some insights into reducing the undesirable damage process for practical applications.
