ABSTRACT
Quantum lithography (QL) has been suggested as a means of achieving enhanced spatial resolution for optical imaging, but its realization has been held back by the low multiphoton detection rates of recording materials. Recently, an optical centroid measurement (OCM) procedure was proposed as a way to obtain spatial resolution enhancement identical to that of QL but with higher detection efficiency (M. Tsang, Phys. Rev. Lett. 102, 253601 (2009)). Here we describe a variation of the OCM method with still higher detection efficiency based on the use of photon-number-resolving detection. We also report laboratory results for two-photon interference. We compare these results with those of the standard QL method based on multiphoton detection and show that the new method leads to superresolution but with higher detection efficiency.
ABSTRACT
BACKGROUND/AIMS: Elderly patients with advanced gastric cancer (AGC) have generally been excluded from clinical trials, and there are few data available on the treatment of these patients. The efficacy of palliative S-1 monotherapy as a first-line treatment regimen for elderly patients has not been well elucidated. METHODS: For this study, 25 AGC patients were enrolled between January 1, 2007 and March 31, 2009; 4 cases were recurrent AGC and 21 cases were metastatic AGC at the time of diagnosis. These patients received S-1 therapy at a dose of 40 mg/m(2) twice daily for 14 days every 3 weeks. All of the patients were older than 70 years. RESULTS: The median follow-up duration, the median progression-free survival, and the overall survival time were 8.7 months (range, 4.9 to 12.5 months), 4.9 months (range, 3.5 to 6.3 months), and 10.8 months (range, 6.6 to 15.0 months), respectively. Grade 3/4 nonhematologic toxicities were rare. Grade 3/4 neutropenia was noted in two patients. The partial response rate was 21.7% and stable disease was observed in 34.8% of the patients. Two patients (8%) died due to chemotherapy-associated toxicity during treatment (septic shock/intracranial hemorrhage). CONCLUSIONS: Oral S-1 chemotherapy seems to be effective as a first-line treatment regimen for elderly patients with metastatic or recurrent AGC. However, elderly patients receiving S-1 treatment should undergo continuous toxicity monitoring, since they are highly susceptible to adverse effects.
ABSTRACT
We measure the nonlinear susceptibility of Bi(3.25)La(0.75)Ti(3)O(12) (BLT) thin films grown on quartz substrates using the Z-scan technique with picosecond laser pulses at a wavelength of 532 nm. The third-order nonlinear refractive index coefficient gamma and absorption coefficient beta of the BLT thin film are 3.1 x 10(-10) cm(2)/W and 3 x 10(-5) cm/W, respectively, which are much larger than those of most ferroelectric films. The results show that the BLT thin films on quartz substrates are good candidate materials for applications in nonlinear optical devices.
ABSTRACT
When a pulse superposed on a cw background propagates through an erbium-doped fiber amplifier with a negative group velocity, either pulse broadening or pulse compression can be observed. These effects can be explained in terms of two competing mechanisms: gain recovery and pulse spectrum broadening. The distortion of the pulse shape caused by these effects depends on input pulse width, pump power, and background-to-pulse power ratio. With the proper choice of these three parameters, we can obtain significant pulse advancement with minimal pulse distortion.
ABSTRACT
The microstructure of a poled surface-relief grating of an azobenzene side-chain polymer film is investigated. From the in situ monitoring of diffraction efficiency and second-harmonic generation, as well as dynamic-contact electrostatic force microscopy images, the point group symmetry of C2nu is identified. The polarization-dependent electro-optic measurement of the reflected diffraction order further confirms the optically biaxial structure of the poled surface-relief grating.
