Oscar Martinez - Academia.edu (original) (raw)
Papers by Oscar Martinez
Optics Letters, 1991
A direct measurement of the amplitude and the phase of a femtosecond light pulse is performed for... more A direct measurement of the amplitude and the phase of a femtosecond light pulse is performed for the first time to our knowledge. The measurement is made in the frequency domain, and the time dependence of the field can be easily obtained by a Fourier transform. The technique relies on a pulse synthesis scheme to unravel the frequency dependence of the phase. A mask filters the spectrum, which gives rise to a pulse with a measurable temporal profile related to the frequency dependence of the phase. In particular, with a rectangular slit the time delay of the synthesized pulse is the first derivative of the phase with respect to the frequency of the original pulse at the central frequency of the filter. The amplitude of the spectrum is obtained from the power spectrum.
Optics Communications, 1992
We study the effect of fluctuations of the input pulse on our method of phase measurement of ultr... more We study the effect of fluctuations of the input pulse on our method of phase measurement of ultrashort light pulses in the frequency domain. We show that the method is nearly insensitive to fluctuations in the input pulse. An estimate is given for the second order correction that results. In our derivation we employ Glauber's P representation, so that our result holds for all classical states and those quantum ones that have P representation. Some results that we obtain are not restricted to our particular case, but are still applicable to other correlation measurements. Investigador independiente del CONICET.
Optics Communications, 1986
Analytical expressions are found for the propagation of the ampfitude of tilted ultrashort pulses... more Analytical expressions are found for the propagation of the ampfitude of tilted ultrashort pulses. The distortions arising are the pulse broadening, tilt angle decrease, chirp, frequency shift and spatial profile variation. Expressions for these quantities are found and it is shown that the mechanisms responsible for the distortions are the group velocity dispersion and the spectral lateral walkoff. The conditions to be met in order to avoid such distortions are derived.
IEEE Journal of Quantum Electronics, 1989
Page 1. 2464 IEEE JOURNAL OF QUANTUM ELECTRONICS. VOL 25. NO 12. DECEMBER 1989 a Achromatic Phase... more Page 1. 2464 IEEE JOURNAL OF QUANTUM ELECTRONICS. VOL 25. NO 12. DECEMBER 1989 a Achromatic Phase Matchng ' for Second HarmoMc* Generation of Femtosecond Pulses * , .. OSCAR EDUARDO MART~NEZ , . ...
Ultrasonics, 2004
Based on the impulse response and the discrete representation methods, a 3D computational method ... more Based on the impulse response and the discrete representation methods, a 3D computational method has been developed to calculate the optimal focal laws to focus the ultrasonic beams through interfaces of complex geometry, and the respective transmitted ultrasonic field generated by NDE transducer arrays. 1- and 2D array transducers are considered. Two different focusing techniques are used to obtain the time delays: the first travel time on each center of the array element, and the cross correlation between the simulated signals from neighboring array elements. Applying the time delays to the array, the transmitted field can be simulated using the same computational method. Several simulations were performed to present the ability of the computational method to focus through, for instance, curved and plane surfaces between two media (acrylic–steel). A comparison between the two focusing techniques is presented.
IEEE Journal of Quantum Electronics, 1991
A detailed analysis of a method of phase measurement of ultrashort light pulses is performed. It ... more A detailed analysis of a method of phase measurement of ultrashort light pulses is performed. It is shown that the output pulse of a zero dispersion compressor with a mask consisting of a narrow slit is a wide pulse delayed an amount equal to the phase derivative of the field spectrum with respect to frequency. State criteria to determine whether the approximations are valid are presented. The method is not affected by artifacts coming from diffraction effects in the slit or by the fact that only correlations are measured. The effects of the errors in positioning the elements are considered and minimized in the construction of the experimental apparatus. A novel technique for measurement of the derivative of the cross correlation is described, and it is used to locate the delayed output pulse
IEEE Journal of Quantum Electronics, 1987
A system that expands and recompresses an ultrashort pulse by means of diffraction gratings is de... more A system that expands and recompresses an ultrashort pulse by means of diffraction gratings is described. The expansion can be large enough to broaden the pulse to several nanoseconds. In this manner, as the signal and pump pulses have similar lengths, high-efficiency amplifiers can be designed. The expansion avoids inefficient energy storage in high-gain amplifiers and nonlinear effects in the
Journal of The Optical Society of America, 1985
We examine passive mode locking, to which not only net-gain saturation but also group-velocity di... more We examine passive mode locking, to which not only net-gain saturation but also group-velocity dispersion and self-phase modulation contribute significantly. Different sources of self-phase modulation are considered, and closed-form analytical solutions are obtained. The case of the colliding-pulse mode locking is discussed, and an ideal case is considered, in which the self-phase modulation and group-velocity dispersion are balanced so as to take maximum advantage of this additional shaping mechanism. This mechanism is shown to be similar to that which causes solitons in optical fibers; it provides additional reduction of the pulse width and significantly improves the stability against fluctuations in net gain.
IEEE Journal of Quantum Electronics, 1988
Absrracr-A matrix formalism for grating and prism compressors is introduced. It is an extension o... more Absrracr-A matrix formalism for grating and prism compressors is introduced. It is an extension of the standard ABCD matrix formalism for Gaussian optics, but includes the possibility of considering disper-sive elements such as gratings and prisms. The full information on the frequency ...
Journal of The Optical Society of America, 1986
Page 1. Vol. 3, No. 7/July 1986/J. Opt. Soc. Am. B 929 Grating and prism compressors in the case ... more Page 1. Vol. 3, No. 7/July 1986/J. Opt. Soc. Am. B 929 Grating and prism compressors in the case of finite beam size 0. E. Martinez CEILAP, CITEFA-CONICET, 1603 V. Martelli, Pcia. Buenos Aires, Argentina Received September 20, 1985; accepted March 10, 1986 ...
Optics Letters, 1991
A direct measurement of the amplitude and the phase of a femtosecond light pulse is performed for... more A direct measurement of the amplitude and the phase of a femtosecond light pulse is performed for the first time to our knowledge. The measurement is made in the frequency domain, and the time dependence of the field can be easily obtained by a Fourier transform. The technique relies on a pulse synthesis scheme to unravel the frequency dependence of the phase. A mask filters the spectrum, which gives rise to a pulse with a measurable temporal profile related to the frequency dependence of the phase. In particular, with a rectangular slit the time delay of the synthesized pulse is the first derivative of the phase with respect to the frequency of the original pulse at the central frequency of the filter. The amplitude of the spectrum is obtained from the power spectrum.
Applied Optics, 2002
We have developed a method for calibrating subnanometer movements of a piezoelectric actuator wit... more We have developed a method for calibrating subnanometer movements of a piezoelectric actuator with picometer accuracy and for a wide range of frequencies. This range make this calibration useful for scanning probe microscopes, particularly for an apertureless scanning near-field optical microscope in which the tip is dithered to modulate the optical signal. The setup consists of a Michelson interferometer that has a mobile arm capable of moving more than one fringe. The piezoelectric actuator to be calibrated vibrates at the desired frequency in the other arm. Net displacement can be calculated by simultaneous measurement of an interferometric signal and its derivative. Hysteresis of the system can be also measured. It will be shown that the actuator response is linear only for the low-frequency region ͑in our case as much as approximately 10 kHz͒. Above that frequency range, higher harmonics appear and cannot be neglected to obtain real displacement. Finally, it will be shown that the use of higher harmonics in calibration or detection schemes ͑that rely on the linearity of the response͒ must be validated, and this technique has proved adequate for that purpose.
Optics Letters, 1991
A direct measurement of the amplitude and the phase of a femtosecond light pulse is performed for... more A direct measurement of the amplitude and the phase of a femtosecond light pulse is performed for the first time to our knowledge. The measurement is made in the frequency domain, and the time dependence of the field can be easily obtained by a Fourier transform. The technique relies on a pulse synthesis scheme to unravel the frequency dependence of the phase. A mask filters the spectrum, which gives rise to a pulse with a measurable temporal profile related to the frequency dependence of the phase. In particular, with a rectangular slit the time delay of the synthesized pulse is the first derivative of the phase with respect to the frequency of the original pulse at the central frequency of the filter. The amplitude of the spectrum is obtained from the power spectrum.
Optics Communications, 1992
We study the effect of fluctuations of the input pulse on our method of phase measurement of ultr... more We study the effect of fluctuations of the input pulse on our method of phase measurement of ultrashort light pulses in the frequency domain. We show that the method is nearly insensitive to fluctuations in the input pulse. An estimate is given for the second order correction that results. In our derivation we employ Glauber's P representation, so that our result holds for all classical states and those quantum ones that have P representation. Some results that we obtain are not restricted to our particular case, but are still applicable to other correlation measurements. Investigador independiente del CONICET.
Optics Communications, 1986
Analytical expressions are found for the propagation of the ampfitude of tilted ultrashort pulses... more Analytical expressions are found for the propagation of the ampfitude of tilted ultrashort pulses. The distortions arising are the pulse broadening, tilt angle decrease, chirp, frequency shift and spatial profile variation. Expressions for these quantities are found and it is shown that the mechanisms responsible for the distortions are the group velocity dispersion and the spectral lateral walkoff. The conditions to be met in order to avoid such distortions are derived.
IEEE Journal of Quantum Electronics, 1989
Page 1. 2464 IEEE JOURNAL OF QUANTUM ELECTRONICS. VOL 25. NO 12. DECEMBER 1989 a Achromatic Phase... more Page 1. 2464 IEEE JOURNAL OF QUANTUM ELECTRONICS. VOL 25. NO 12. DECEMBER 1989 a Achromatic Phase Matchng ' for Second HarmoMc* Generation of Femtosecond Pulses * , .. OSCAR EDUARDO MART~NEZ , . ...
Ultrasonics, 2004
Based on the impulse response and the discrete representation methods, a 3D computational method ... more Based on the impulse response and the discrete representation methods, a 3D computational method has been developed to calculate the optimal focal laws to focus the ultrasonic beams through interfaces of complex geometry, and the respective transmitted ultrasonic field generated by NDE transducer arrays. 1- and 2D array transducers are considered. Two different focusing techniques are used to obtain the time delays: the first travel time on each center of the array element, and the cross correlation between the simulated signals from neighboring array elements. Applying the time delays to the array, the transmitted field can be simulated using the same computational method. Several simulations were performed to present the ability of the computational method to focus through, for instance, curved and plane surfaces between two media (acrylic–steel). A comparison between the two focusing techniques is presented.
IEEE Journal of Quantum Electronics, 1991
A detailed analysis of a method of phase measurement of ultrashort light pulses is performed. It ... more A detailed analysis of a method of phase measurement of ultrashort light pulses is performed. It is shown that the output pulse of a zero dispersion compressor with a mask consisting of a narrow slit is a wide pulse delayed an amount equal to the phase derivative of the field spectrum with respect to frequency. State criteria to determine whether the approximations are valid are presented. The method is not affected by artifacts coming from diffraction effects in the slit or by the fact that only correlations are measured. The effects of the errors in positioning the elements are considered and minimized in the construction of the experimental apparatus. A novel technique for measurement of the derivative of the cross correlation is described, and it is used to locate the delayed output pulse
IEEE Journal of Quantum Electronics, 1987
A system that expands and recompresses an ultrashort pulse by means of diffraction gratings is de... more A system that expands and recompresses an ultrashort pulse by means of diffraction gratings is described. The expansion can be large enough to broaden the pulse to several nanoseconds. In this manner, as the signal and pump pulses have similar lengths, high-efficiency amplifiers can be designed. The expansion avoids inefficient energy storage in high-gain amplifiers and nonlinear effects in the
Journal of The Optical Society of America, 1985
We examine passive mode locking, to which not only net-gain saturation but also group-velocity di... more We examine passive mode locking, to which not only net-gain saturation but also group-velocity dispersion and self-phase modulation contribute significantly. Different sources of self-phase modulation are considered, and closed-form analytical solutions are obtained. The case of the colliding-pulse mode locking is discussed, and an ideal case is considered, in which the self-phase modulation and group-velocity dispersion are balanced so as to take maximum advantage of this additional shaping mechanism. This mechanism is shown to be similar to that which causes solitons in optical fibers; it provides additional reduction of the pulse width and significantly improves the stability against fluctuations in net gain.
IEEE Journal of Quantum Electronics, 1988
Absrracr-A matrix formalism for grating and prism compressors is introduced. It is an extension o... more Absrracr-A matrix formalism for grating and prism compressors is introduced. It is an extension of the standard ABCD matrix formalism for Gaussian optics, but includes the possibility of considering disper-sive elements such as gratings and prisms. The full information on the frequency ...
Journal of The Optical Society of America, 1986
Page 1. Vol. 3, No. 7/July 1986/J. Opt. Soc. Am. B 929 Grating and prism compressors in the case ... more Page 1. Vol. 3, No. 7/July 1986/J. Opt. Soc. Am. B 929 Grating and prism compressors in the case of finite beam size 0. E. Martinez CEILAP, CITEFA-CONICET, 1603 V. Martelli, Pcia. Buenos Aires, Argentina Received September 20, 1985; accepted March 10, 1986 ...
Optics Letters, 1991
A direct measurement of the amplitude and the phase of a femtosecond light pulse is performed for... more A direct measurement of the amplitude and the phase of a femtosecond light pulse is performed for the first time to our knowledge. The measurement is made in the frequency domain, and the time dependence of the field can be easily obtained by a Fourier transform. The technique relies on a pulse synthesis scheme to unravel the frequency dependence of the phase. A mask filters the spectrum, which gives rise to a pulse with a measurable temporal profile related to the frequency dependence of the phase. In particular, with a rectangular slit the time delay of the synthesized pulse is the first derivative of the phase with respect to the frequency of the original pulse at the central frequency of the filter. The amplitude of the spectrum is obtained from the power spectrum.
Applied Optics, 2002
We have developed a method for calibrating subnanometer movements of a piezoelectric actuator wit... more We have developed a method for calibrating subnanometer movements of a piezoelectric actuator with picometer accuracy and for a wide range of frequencies. This range make this calibration useful for scanning probe microscopes, particularly for an apertureless scanning near-field optical microscope in which the tip is dithered to modulate the optical signal. The setup consists of a Michelson interferometer that has a mobile arm capable of moving more than one fringe. The piezoelectric actuator to be calibrated vibrates at the desired frequency in the other arm. Net displacement can be calculated by simultaneous measurement of an interferometric signal and its derivative. Hysteresis of the system can be also measured. It will be shown that the actuator response is linear only for the low-frequency region ͑in our case as much as approximately 10 kHz͒. Above that frequency range, higher harmonics appear and cannot be neglected to obtain real displacement. Finally, it will be shown that the use of higher harmonics in calibration or detection schemes ͑that rely on the linearity of the response͒ must be validated, and this technique has proved adequate for that purpose.