Longitudinal iso-phase condition and needle pulses.
نویسندگان
چکیده
We study the properties of pulsed solutions to the scalar and vector wave equations composed of plane-waves with equal longitudinal spatial frequency. This condition guarantees that, at all times, the field profile is invariant in the longitudinal direction. Particular emphasis is placed on solutions with rotational symmetry. For these solutions, the wave concentrates strongly near the axis at a given time. We provide closed-form expressions for some of these fields, and show that their wavefronts are approximately spherical. Solutions carrying orbital and spin angular momenta are also considered.
منابع مشابه
Ultralong pure longitudinal magnetization needle induced by annular vortex binary optics.
In this Letter, based on the Richards and Wolf diffraction theory, an ultralong optical needle with pure transverse polarization is numerically generated by tightly focusing an azimuthally polarized beam through an annular vortex binary filter. Such an ultralong transversely polarized optical needle is generated through the π phase shift between adjacent rings of the binary filter. We show that...
متن کاملBalanced SSFP & Modifications for Unique Contrast
The term “steady state” refers to the equilibrium condition that evolves when magnetization experiences a train of radiofrequency (RF) pulses. If RF pulses are applied on the order of seconds (TR≈T1), the magnetization decays away completely in the transverse plane between RF pulses, but may not recover fully along the longitudinal axis. In the resulting steady state, the magnetization tipped a...
متن کاملNeedle-tip localization using an optical fibre hydrophone
Ultrasound imaging is frequently used for guiding needles during minimally invasive procedures, but accurate identification of the needle tips can be challenging, even for experienced practitioners. In this study, a novel method for tracking needles inside the human body was developed. This method, called ultrasonic device tracking (UDT), involved the detection of ultrasound pulses from the ext...
متن کاملEffects of intense laser pulse properties on wake field acceleration in magnetized plasma: Half-Sine Shape (HSS) and Gaussian Shape (GS) pulses
In this paper, we have simulated the excitation of wake fields in the interaction of an intensive laser pulses having Half-Sine and Gaussian time envelopes with a fully ionized cold plasma using particle in cell (PIC) method. We investigated the dependency of wake filed amplitude to different laser and plasma parameters such as laser wavelength, pulse duration and electron number density. In ad...
متن کاملMode-locking of a CW laser
Short pulses are useful in a number of applications in optics, e.g., time resolved spectroscopy, sampling of fast electronics, and communications. This has led to a number of mode-locking techniques to obtain such pulses, for example acousto-optic, injection, synchronous-pump, collidingpulse mode-locking, and Kerr-lens mode-locking. Using the latter two techniques, pulses of less than 100 fs du...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Optics express
دوره 24 25 شماره
صفحات -
تاریخ انتشار 2016