The optical microcavity effect of the homo-tandem solar cells is explored utilizing the transfer matrix method. Ultrathin silver can reduce the deadzone effect compared with graphene and PH1000, and leads to a factor ...The optical microcavity effect of the homo-tandem solar cells is explored utilizing the transfer matrix method. Ultrathin silver can reduce the deadzone effect compared with graphene and PH1000, and leads to a factor of 1.07 enhancement for an electrical field in a metal microcavity. The enhancement is considered to be the fact that strong exciton-photon coupling occurs in the microcavity due to ultrathin Ag. On the basis of the optical enhancement effect, optical behaviors are manipulated by varying the microcavity length. It is confirmed that ultrathin silver can serve as an ideal interconnection layer as the active layer is ～ 150nm thick and the thickness ratio between front and rear active layers lies between 1：1 and 1：2.展开更多
For the measurement of vertical profiles of sound speed in the sea using laser excited Brillouin scattering, a high resolution measurement of Brillouin frequency shift is required. In this work, a molecular absorption...For the measurement of vertical profiles of sound speed in the sea using laser excited Brillouin scattering, a high resolution measurement of Brillouin frequency shift is required. In this work, a molecular absorption cell was selected as the frequency shift discriminator and several kinds of absorption gases were tried. It was found that the strong line (#1095) of 127 I 2 at 18783.3297 cm -1 and two absorption lines of 129 I 2 located at the two sides of the #1095 line of 127 I 2 could be used as frequency shift discriminator to detect the changes of the Brillouin frequency shift. This selection is the best one within the range from 532.0131 nm to 532.5154 nm. But it is not perfect and there is a lot of work to do before its practical application.展开更多
A compact multipass cell with low fringes and high thermal stability is described. This cell is formed by two twisted cylindrical mirrors. The optical parameters are determined based on the selection criteria, which i...A compact multipass cell with low fringes and high thermal stability is described. This cell is formed by two twisted cylindrical mirrors. The optical parameters are determined based on the selection criteria, which include mirror filling efficiency, ~nterference fringes, and pattern stability. With a pattern of 174 passes, this cell gives a 22-m path length in a volume of 0.55 L. The results of an absorption measurement of oxygen at 13 091.7 cm-1 show that the fringe noise is lower than 6.54~10-4. The maximum allowed temperature change to keep the beam from exiting is 33 K, which indicates high stability against thermal drift.展开更多
Frequency-domain photoacoustic (PA) technique for immediate measuring absolute optical absorption coefficient is presented. It is based on determination of the ratio of the two spectrum amplitudes of the differential ...Frequency-domain photoacoustic (PA) technique for immediate measuring absolute optical absorption coefficient is presented. It is based on determination of the ratio of the two spectrum amplitudes of the differential PA signal. The sample is placed into the lateral chamber of a three chamber PA cell. The difference of pressure variations (differential PA signal) excited in two other chambers as a result of laser pulse absorption by the sample is recorded. Presented PA technique was tested experimentally by measuring water absorption coefficient at an IR wavelength.展开更多
Optical absorption in thin-film solar cells can be improved by using surface plasmons for guiding and confining the light on the nanoscale.We report theoretical and simulation studies of a-Si thin-film solar cells wit...Optical absorption in thin-film solar cells can be improved by using surface plasmons for guiding and confining the light on the nanoscale.We report theoretical and simulation studies of a-Si thin-film solar cells with silver nanocylinders on the surface.We found that surface plasmons increased the cells＇ spectral response over almost the entire studied solar spectrum.In the ultraviolet range and at wavelengths close to the Si band gap we observed a significant enhancement of the absorption for both thin-film and wafer-based structures.We also performed optimization studies of particle size,inter-particle distance,and dielectric environment,for obtaining maximal absorption within the substrate.A blue-shift of the resonance wavelength with increasing inter-particle distance was observed in the visible range.Cell performance improved at optimal spacing,which strongly depended on the nanoparticle size.Increasing the nanocylinder size was accompanied by the widening of the plasmon resonance band and a red-shift of the plasmon resonance peaks.A weak red-shift and plasmon peak enhancement were observed in the reflectance curve with increasing refractive index of the dielectric spacer.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 61565015the Western Light Talent Training Program of Chinese Academy of Sciences
文摘The optical microcavity effect of the homo-tandem solar cells is explored utilizing the transfer matrix method. Ultrathin silver can reduce the deadzone effect compared with graphene and PH1000, and leads to a factor of 1.07 enhancement for an electrical field in a metal microcavity. The enhancement is considered to be the fact that strong exciton-photon coupling occurs in the microcavity due to ultrathin Ag. On the basis of the optical enhancement effect, optical behaviors are manipulated by varying the microcavity length. It is confirmed that ultrathin silver can serve as an ideal interconnection layer as the active layer is ～ 150nm thick and the thickness ratio between front and rear active layers lies between 1：1 and 1：2.
文摘For the measurement of vertical profiles of sound speed in the sea using laser excited Brillouin scattering, a high resolution measurement of Brillouin frequency shift is required. In this work, a molecular absorption cell was selected as the frequency shift discriminator and several kinds of absorption gases were tried. It was found that the strong line (#1095) of 127 I 2 at 18783.3297 cm -1 and two absorption lines of 129 I 2 located at the two sides of the #1095 line of 127 I 2 could be used as frequency shift discriminator to detect the changes of the Brillouin frequency shift. This selection is the best one within the range from 532.0131 nm to 532.5154 nm. But it is not perfect and there is a lot of work to do before its practical application.
基金supported by the National Key Scientifc Instrument and Equipment Development Project under Grant No.2012YQ22011902
文摘A compact multipass cell with low fringes and high thermal stability is described. This cell is formed by two twisted cylindrical mirrors. The optical parameters are determined based on the selection criteria, which include mirror filling efficiency, ~nterference fringes, and pattern stability. With a pattern of 174 passes, this cell gives a 22-m path length in a volume of 0.55 L. The results of an absorption measurement of oxygen at 13 091.7 cm-1 show that the fringe noise is lower than 6.54~10-4. The maximum allowed temperature change to keep the beam from exiting is 33 K, which indicates high stability against thermal drift.
文摘Frequency-domain photoacoustic (PA) technique for immediate measuring absolute optical absorption coefficient is presented. It is based on determination of the ratio of the two spectrum amplitudes of the differential PA signal. The sample is placed into the lateral chamber of a three chamber PA cell. The difference of pressure variations (differential PA signal) excited in two other chambers as a result of laser pulse absorption by the sample is recorded. Presented PA technique was tested experimentally by measuring water absorption coefficient at an IR wavelength.
文摘Optical absorption in thin-film solar cells can be improved by using surface plasmons for guiding and confining the light on the nanoscale.We report theoretical and simulation studies of a-Si thin-film solar cells with silver nanocylinders on the surface.We found that surface plasmons increased the cells＇ spectral response over almost the entire studied solar spectrum.In the ultraviolet range and at wavelengths close to the Si band gap we observed a significant enhancement of the absorption for both thin-film and wafer-based structures.We also performed optimization studies of particle size,inter-particle distance,and dielectric environment,for obtaining maximal absorption within the substrate.A blue-shift of the resonance wavelength with increasing inter-particle distance was observed in the visible range.Cell performance improved at optimal spacing,which strongly depended on the nanoparticle size.Increasing the nanocylinder size was accompanied by the widening of the plasmon resonance band and a red-shift of the plasmon resonance peaks.A weak red-shift and plasmon peak enhancement were observed in the reflectance curve with increasing refractive index of the dielectric spacer.
