CLEO '97., Summaries of Papers Presented at the Conference on Lasers and Electro-Optics最新文献

{"title":"Multiple wavelength operation of a unidirectional Er-doped fiber ring laser with optical feedback","authors":"Y. Zhao, C. Shu, S.P. Li, H. Ding, K. Chan","doi":"10.1109/CLEO.1997.603327","DOIUrl":"https://doi.org/10.1109/CLEO.1997.603327","url":null,"abstract":"Multiple wavelength laser operation in the 1.55 p m lowest-loss window has attracted a great attention recently because of its potential application in wavelength division multiplexed communication.’-’ We report here a equal power output, narrow bandwidth, and parasitic oscillation-free Er-doped fiber unidirectional ring laser using optical feedback. Figure 1 shows the configuration of this new ring laser. Fiber gratings are used as wavelength-selective elements. Both the polarization-sensitive isolator and the polarization controller PC1 keep the ring laser operating in unidirection preventing from two directional spatial mode competition. Meanwhile, through altering the polarization states of the multiwavelength lasing oscillation via adjusting the PCl, roughly equal power oscillation may be obtained. The closed lasing circulation path is A+B+C+D+E-+A, while the feedback path is B+F-+G+A. Assuming that the laser power at X, is P, at point B under stable state oscillation, and ignoring the insertion loss of the devices such as CP1 and CP2 as well as fiber gratings, the selected power by the fiber grating with center frequency Ai is 0.25RR,P,, optical feedback is 0.5( l-R)P,, and the laser output is [0.5R2 + 0.5(1-R)’ + 0.25R( 1-R)R,]P,, where R is the coupling ratio of the CP 1 and R, is the reflectivity of the fiber grating. 10 ni Er-doped fiber with doping concentration of4.4 X 10” cm-’, pumped at 980 nm, provides a gain to balance the ring cavity loss. The polarization controller PC2 is added into the feedback path so as to match the polarization state of the feedback with that in the ring cavity. We have compared the cases of R = 1 (without feedback), 0.9 (weak feedback), and 0.7 (large feedback). The experimental results show that optical feedback provides the following three advantages: (1) Stable laser operation with equal power outputs can be realized by optical feedback that functions through adjusting the dynamic inhomoge-","PeriodicalId":173652,"journal":{"name":"CLEO '97., Summaries of Papers Presented at the Conference on Lasers and Electro-Optics","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122048507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coherent terahertz detection: free space electro-optic sampling versus antenna detection","authors":"I. Brener, Q. Wu, Y. Cai, X. Zhang, J. Lopata, J. Wynn, L. Pfeiffer, J. Stark, J. Federici","doi":"10.1109/CLEO.1997.602359","DOIUrl":"https://doi.org/10.1109/CLEO.1997.602359","url":null,"abstract":"The recent surge of interest in ytterbium-based lasers is focused on high-power diode-pumped all-solid-state laser sources. One of the advantages of the Yb3+ ion are the relatively broad absorption and emission bands. They are much smoother and display less structure in glass host materials than those of %:YAG, a promising feature for tunable operation and generation of ultrashort laser pulses. Efficient diode pumping of %:glass has already been demonstrated under continuous-wave conditions.'32 The first attempt to modelock the %:YAG laser by a passive method (A-FPSA) resulted in 540-fs-long pulses at 1.03 I J . ~ . ~ Here we demonstrate cw passive modelocking of an %:glass laser for the first time to our knowledge, based entirely on the Kerr effect in the active medium in a resonator with dispersion compensation. The glass sample used was doped with 6 X 10' cm-3 Yb3+ and exhibits a fluorescence lifetime of 1.2 ms. In our experiments a cw Tksapphire laser acts as the pump source. The output of the pump laser (3 W at 940 nm) was focused into the 4-mm-thick %:glass sample by a 60 mm lens. The active material was positioned at the Brewster angle between two folding mirrors in a standard astigmatically compensated type-Z laser configuration (Fig. 1). The cavity could be operated as a free-running cw laser by use of M, (Fig. 1) yielding >350 mW ofoutput power near 1035 nm at 1.2 W of absorbed pump radiation with a threshold of -150 mW. Essential for the achievement of pure passive modelocking was the minimization of all losses at the maximum pump power available. After optimization in the cw free-running regime modelocked operation was achieved then by precise adjustment of the two prisms, the %:glass sample and the 3-mm-wide vertical slit employed as an aperture near the output coupler Mi. Starting of the laser was accomplished through slow translation of one of the","PeriodicalId":173652,"journal":{"name":"CLEO '97., Summaries of Papers Presented at the Conference on Lasers and Electro-Optics","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124627694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tissue optical characterization with use of immersion and frequency domain measurements","authors":"Xingkun Wu, G. Faris","doi":"10.1109/CLEO.1997.602389","DOIUrl":"https://doi.org/10.1109/CLEO.1997.602389","url":null,"abstract":"Confocal microscopes have important applications in biology and neural sciences. Right now most of commercial confocal microscopes use mechanical scanning mechanisms to generate confocal images, e.g., using mirrors .to scan a laser beam across the field ofview, or using a rotating disk to scan across the field of view. These confocal systems limit the confocal scanning to only a raster scanning format. They do not offer externally gated and controllable illumination and imaging frames, fields, and subsets. Using the digital micromirror device (DMD) technology, we have developed a confocal microscope system that uses the DMD as a binary spatial light modulator to provide confocal scanning and offers flexible operating modes. For example, users can generate confocal images over any areas of interest, they can easily control the axial resolution, and they can also easily switch between confocal imaging modes and other microscopic imaging modes. The constructed prototype used one DMD for both the illumination aperture and detection aperture. This structure offers a robust system alignment and lowers the synchronization requirements. A reflective imaging system was used to relay the illumination patterns onto a sample and to relay confocal images onto a two-dimensional detector [e.g., charge injection device (CID)]. This design made the whole confocal imaging system less sensitive to chromatic aberration errors. We have built a computer simulation model to associate the performance parameters of a confocal imaging system (such as transversal resolution, axial resolution, and temporal resolution) with the confocal parameters of the DMD (such as confocal pattern period, pixel size, contrast ratio, etc.). Optical experiments were conducted to verify the computer simulation model. The experimental results have confirmed the computer simulation. The experiments showed that good confocal images can be obtained even when the confocal pattern period is as short as five times the aperture size. Right now the consensus for the confocal pattern period is about 10 times the aperture size. Based on our results we can improve the temporal resolution of a confocal imaging system by four times. Because of the nature of programmable confocal patterns, users can trade off among transversal resolution, axial resolution, and temporal resolution by changing the confocal parameters of the DMD. The details of the theoretical analysis, system construction, and experimental results are reported.","PeriodicalId":173652,"journal":{"name":"CLEO '97., Summaries of Papers Presented at the Conference on Lasers and Electro-Optics","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124643648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Imaging through scattering media with use of photorefractive polymers","authors":"B. Volodin, D. Steele, B. Kippelen, N. Peyghambarian","doi":"10.1109/CLEO.1997.602439","DOIUrl":"https://doi.org/10.1109/CLEO.1997.602439","url":null,"abstract":"In the treatment of cancer and macular degeneration with photodynamic therapy (PDT), a class of photosensitizing compounds has been developed by a number of drug companies that are either selectively retained in or are preferentially produced by tumor cells. These dyelike molecules, when exposed to laser light in the visible or UV region, are excited to the triplet state where they have the capacity to promote molecular oxygen to its first excited singlet (IO2). This species is believed to be cytotoxic and causes local necrosis of the tumor cells. However, one particular drawback of the technique is the limit in penetration depth inherent in using visible light as an activation mechanism. Furthermore, treatment of internal cancer sites is necessarily invasive, requiring the use of fiber-optic catheters, endoscopes, or similar instruments. Another activation pathway for this procedure is suggested by results obtained by applying ultrasound to peroxyoxalate chemiluminescent systems (PO CL). In these systems, oxalic acid derivatives react with hydrogen peroxide in the presence of a fluorophore to produce a bright emission characteristic of the fluorescer. This reaction proceeds via an energetic key intermediate, which is proposed to be 1,2-dioxetanedione. In a recent set of experiments, we have observed that when the ester bis(2,4dinitrophenyl) oxalate (DNPO) and the fluorescer rubrene in dimethyl phthalate (DMP) are sonicated with an ultrasonic bath, light is produced at appreciable levels without the addition of hydrogen peroxide. The greatest intensity is observed at the antinodes of the standing waves produced by the sonication bath (Fig. 1). Additionally, the threshold behavior of the CL intensity versus ultrasound power (Fig. 2) suggests that the reactive species","PeriodicalId":173652,"journal":{"name":"CLEO '97., Summaries of Papers Presented at the Conference on Lasers and Electro-Optics","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124815442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Airborne Differential Absorption Lidar (DIAL) and its evolution to space","authors":"E. Browell","doi":"10.1109/CLEO.1997.602417","DOIUrl":"https://doi.org/10.1109/CLEO.1997.602417","url":null,"abstract":"","PeriodicalId":173652,"journal":{"name":"CLEO '97., Summaries of Papers Presented at the Conference on Lasers and Electro-Optics","volume":"117 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125051006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Self-consistent approach for the determination of effective differential gain and effective capture time in multiple-quantum-well lasers","authors":"A.G. Plyavenek, A.V. Lyubarskii","doi":"10.1109/CLEO.1997.603072","DOIUrl":"https://doi.org/10.1109/CLEO.1997.603072","url":null,"abstract":"","PeriodicalId":173652,"journal":{"name":"CLEO '97., Summaries of Papers Presented at the Conference on Lasers and Electro-Optics","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128311720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anisotropic charge mobility in KNbO/sub 3/ and BaTiO/sub 3/","authors":"P. Bernasconi, I. Biaggio, G. Montemezzani, P. Gunter","doi":"10.1109/CLEO.1997.602336","DOIUrl":"https://doi.org/10.1109/CLEO.1997.602336","url":null,"abstract":"","PeriodicalId":173652,"journal":{"name":"CLEO '97., Summaries of Papers Presented at the Conference on Lasers and Electro-Optics","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128378052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phase compensation using acousto-optic programmable dispersive filter","authors":"F. Falcoz, F. Estable, P. Tournois","doi":"10.1109/CLEO.1997.603509","DOIUrl":"https://doi.org/10.1109/CLEO.1997.603509","url":null,"abstract":"scheme of future high power laser. Output energy is estimated to be 5 kJ for 3-ns-longpulses. A oscillator is pumped by two cw laser diodes. Stable modelocked pulses were obtained by a solid-state saturable absorber and prism pairs for dispersion compensation. Autocorrelation of the output pulses is shown in Fig. 2. Temporal wave form is well defined by sech' function of 151 fs. Spectrum width is 8.7 nm (2.6 THz). Product (6t X 6v) is 0.39 and nearly Fourier transfer limited. The operation stability was tested for 16 hours. The fluctuation of oscillation wavelength is 20.15 nm and much smaller compared with gain spectrum of the Nd:glass laser. The main amplifier of the new beamline consists of four disk amplifiers with 350-mm aperture in Cassegrain type 3 pass geometry. Each disk amplifier has two LHG-80 disks (694 X 380 X 45). Laser disks are pumped by flashlamps from two sides. The maximum pump energy is about 400 kJ. The performance of the disk amplifier was measured. Small signal gain and pumping efficiency were 1.88 and CFK4 U 3 0 am","PeriodicalId":173652,"journal":{"name":"CLEO '97., Summaries of Papers Presented at the Conference on Lasers and Electro-Optics","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128224445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"230 mW of blue light from thulium: ZBLAN upconvereion fiber laser","authors":"R. Paschotta, N. Moore, W. Clarkson, A. Tropper, D. Hanna, G. Mazé","doi":"10.1109/CLEO.1997.602272","DOIUrl":"https://doi.org/10.1109/CLEO.1997.602272","url":null,"abstract":"230 mW at 481 nm have been obtained from a Tm:ZBLAN upconversion fibre laser, pumped by a Nd:YAG laser with 1.6W at 1123nm. The fibre developed a strong loss which however appeared to be fully reversible","PeriodicalId":173652,"journal":{"name":"CLEO '97., Summaries of Papers Presented at the Conference on Lasers and Electro-Optics","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129310380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Passive Q-switching of fiber lasers with use of a dynamic SBS silica fiber mirror","authors":"S. Chernikov, A. Fotiadi","doi":"10.1109/CLEO.1997.603466","DOIUrl":"https://doi.org/10.1109/CLEO.1997.603466","url":null,"abstract":"standard 2 x 2 sinple-mode fused fiber couDler this was attributed to not being able to prevent v with nominally 5050 coupling ratio at 1.06 pm, and a loop consisting of 9 m of singlemode fiber at 1.06 )*m fusion-spliced to the coupler output arms. Three meters of fiber in the loop were coiled around a piezoelectric cylinder (PZT8) that had dimensions of 1-mm thickness, 5-cm outer diameter, and 1-cm height. The voltage applied to the piezoelectric was used to modulate the overall birefringence of the fiber loop. Phase modulation effects were avoided by placing the fiber coil right at the center of the 9-m loop3; included in this loop was an all-fiber polarization controller that was used to adjust the polarization, and therefore the reflectivity, under cw fiber laser operation. The fiber laser consisted of 6 m of Nddoped single-mode, double-clad fiber; a dielectric dichroic mirror was attached to one end of it (reflectivity 299.5% at 1060 nm and 50.5% at 807 nm) and the other end was coupled through a linear polarizer to the Sagnac output mirror. Cavity dumping (Fig. 1) was observed by application of a harmonic voltage to the piezoelectric element, at a frequency of 2 MHz, which matched a mechanical resonance of it. The voltage amplitude and the polarization controller were adjusted to achieve near 100% modulation of the Sagnac mirror reflectivity. Notice that one pulse per modulation cycle was emitted in a train of cavity-dumped pulses that had a peak power equal to twice the cw power, and pulse widths of 160 ns. This is close to optimum performance, which would predict pulse widths equal to the laser cavity round-trip-time of approximately 150 m4 Q-switching was achieved by first adjusting the polarization controller to give the minimum reflectivity of the Sagnac mirror under cw operation. Then, a voltage impulse with an amplitude of 30 V and a duration of 6 p s was applied to the piezoelectric element. The observed output Q-switched pulses of the laser (Fig. 2) had an energy of 125 nJ and pulse widths of 550 ns, when pumping with 440 mW of pump power. Notice that Q-switching performance is far from optimum, as one would expect to achieve pulse energies comparable to 1 )*I, the saturation energy of the fiber laser; lasing before the voltage impulse is applied. Furthermore, to eliminate low amplitude relaxation oscillations of the fiber laser after the Q-switched pulse is emitted, caused by undesirable mechanical oscillations of the piezoelectric element, it was necessary to modulate the pump with 4-ms pulses as shown in Fig. 2. *Departamento de Fisica Aplicada, Universidad de Valencia, Dr. Moliner 50 461 00, Budassot (Valencia) Spain 1. J. D. Cao et al., CLE0'93 Tech. Digest, paper CFJ3, p. 622 (Baltimore, Md.). 2. L. A. Zenteno, J. Lightwave Technology","PeriodicalId":173652,"journal":{"name":"CLEO '97., Summaries of Papers Presented at the Conference on Lasers and Electro-Optics","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129580213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}