Browsing by Subject "Phase shift"

Now showing 1 - 6 of 6

Open Access
Accumulated Gouy phase shift in Gaussian beam propagation through first-order optical systems
(Optical Society of America, 1997-09) Erden, M. F.; Özaktaş, Haldun M.
We define the accumulated Gouy phase shift as the on-axis phase accumulated by a Gaussian beam in passing through an optical system, in excess of the phase accumulated by a plane wave. We give an expression for the accumulated Gouy phase shift in terms of the parameters of the system through which the beam propagates. This quantity complements the beam diameter and the wave-front radius of curvature to constitute three parameters that uniquely characterize the beam with respect to a reference point in the system. Measurement of these parameters allows one to uniquely recover the parameters characterizing the first-order system through which the beam propagates.
Open Access
Broadband one way propagation via dielectric waveguides with unequal effective index
(IEEE, 2014) Öner, B. B.; Üstün, K.; Kurt, H.; Okyay, Ali Kemal; Turhan-Sayan, G.
We present an efficient approach for broad band one way propagation of light by parallel and unequal dielectric waveguides leading different effective phase shifts. Three dimensional numerical simulations show that 30% operating bandwidth is achieved.
Open Access
Fractional Fourier transform as a tool for analyzing beam propagation and spherical mirror resonators
(Optical Society of America, 1994) Özaktaş, Haldun M.; Mendlovic, D.
The complex amplitude distributions on two spherical reference surfaces of given curvature and spacing are simply related by a fractional Fourier transform. The order of the fractional Fourier transform is proportional to the Gouy phase shift between the two surfaces. This result provides new insight into wave propagation and spherical mirror resonators as well as the possibility of exploiting the fractional Fourier transform as a mathematical tool in analyzing such systems.
Open Access
Improving the accuracy of a time lens
(Optical Society of America, 1997-11) Yurchenko, V. B.
A method for improving the accuracy of temporal imaging with an imperfect time lens is proposed. Signal distortion arising from complicated dispersion of the delay lines can be reduced considerably by appropriate choice of the phase-modulation function including the second harmonic of the basic modulation frequency and a specific phase shift of the modulation with respect to the main signal. The method is of particular interest for picosecond and femtosecond optical pulse generation.
Open Access
Microjoule-energy, 1 MHz repetition rate pulses from all-fiber-integrated nonlinear chirped-pulse amplifier
(Optical Society of America, 2010-03-23) Kalaycioglu, H.; Oktem, B.; Şenel, Ç.; Paltani, P. P.; Ilday, F. Ö.
We demonstrate generation of pulses with up to 4 μJ energy at 1 MHz repetition rate through nonlinear chirped-pulse amplification in an entirely fiber-integrated amplifier, seeded by a fiber oscillator. The peak power and the estimated nonlinear phase shift of the amplified pulses are as much as 57 kW and 22π, respectively. The shortest compressed pulse duration of 140 fs is obtained for 3.1 μJ of uncompressed amplifier output energy at 18 π of nonlinear phase shift. At 4 μJ of energy, the nonlinear phase shift is 22 π and compression leads to 170-fs-long pulses. Numerical simulations are utilized to model the experiments and identify the limitations. Amplification is ultimately limited by the onset of Raman amplification of the longer edge of the spectrum with an uncompressible phase profile.
Open Access
Reconfigurable nested ring-split ring transmitarray unit cell employing the element rotation method by microfluidics
(Institute of Electrical and Electronics Engineers, 2015) Erdil, E.; Topalli, K.; Esmaeilzad, N. S.; Zorlu, O.; Kulah, H.; Aydin, C. O.
A continuously tunable, circularly polarized X-band microfluidic transmitarray unit cell employing the element rotation method is designed and fabricated. The unit cell comprises a double layer nested ring-split ring structure realized as microfluidic channels embedded in Polydimethylsiloxane (PDMS) using soft lithography techniques. Conductive regions of the rings are formed by injecting a liquid metal (an alloy of Ga, In, and Sn), whereas the split region is air. Movement of the liquid metal together with the split around the ring provides 360° linear phase shift range in the transmitted field through the unit cell. A circularly polarized unit cell is designed to operate at 8.8 GHz, satisfying the necessary phase shifting conditions provided by the element rotation method. Unit cell prototypes are fabricated and the proposed concept is verified by the measurements using waveguide simulator method, within the frequency range of 8-10 GHz. The agreement between the simulation and measurement results is satisfactory, illustrating the viability of the approach to be used in reconfigurable antennas and antenna arrays.