Related Concept Videos
01:17NMR Spectrometers: Radiofrequency Pulses and Pulse Sequences
A pulse is a short burst of radio waves distributed over a range of frequencies that simultaneously excites all the nuclei in the sample. Upon passing a radio frequency pulse along the x-axis, the nuclei absorb energy corresponding to their Larmor frequencies and achieve resonance. This shifts the net magnetization vector from the z-axis toward the transverse plane. This angle of rotation of the magnetization vector, or the flip angle, is proportional to the duration and intensity of the pulse.
01:20Design Example: Capacitance Multiplier Circuit
In integrated circuit technology, a capacitance multiplier is often utilized to produce a larger capacitance value when a small physical capacitance falls short. This is achieved by a circuit that multiplies capacitance values by a factor of up to 1000, such that a 10-pF capacitor can replicate the performance of a 100-nF capacitor.
The circuit illustrated in Figure 1 below incorporates two op-amps, with the first operating as a voltage follower and the second acting as an inverting amplifier.
The circuit illustrated in Figure 1 below incorporates two op-amps, with the first operating as a voltage follower and the second acting as an inverting amplifier.
01:19Rectangular and Triangular Pulse Function
The unit rectangular pulse function is mathematically represented by a rectangular function centered at the origin with a height of one unit. This function is defined by two parameters: T, which specifies the center location of the pulse along the time axis, and τ, which determines the pulse duration.
For example, consider a rectangular pulse with a 5V amplitude, a 3-second duration, and centered at t=2 seconds. This pulse can be expressed using the rectangular function, written as,
For example, consider a rectangular pulse with a 5V amplitude, a 3-second duration, and centered at t=2 seconds. This pulse can be expressed using the rectangular function, written as,
01:12Double Resonance Techniques: Overview
Double resonance techniques in Nuclear Magnetic Resonance (NMR) spectroscopy involve the simultaneous application of two different frequencies or radiofrequency pulses to manipulate and observe two distinct nuclear spins. One important application of double resonance is spin decoupling, which selectively suppresses coupling with one type of nucleus while observing the NMR signal from another nucleus, simplifying the spectrum and enhancing resolution.
Spin decoupling is usually achieved by...
Spin decoupling is usually achieved by...
01:28Standing Waves in a Cavity
A household microwave and lasers are examples of standing electromagnetic waves in a cavity. When two conducting metal plates are placed parallel at the nodal planes, it creates a cavity where standing waves are formed. The cavity between the two planes is analogous to a stretched string held at the points x = 0 and x = L. Here, the distance 'L' between the two planes must be an integer multiple of half of the wavelength. The wavelengths that satisfy this condition are given by:
01:10Generating Electromagnetic Radiations
The German physicist Heinrich Hertz (1857–1894) was the first to generate and detect certain types of electromagnetic waves in the laboratory. Starting in 1887, he performed a series of experiments that confirmed the existence of electromagnetic waves and verified that they travel at the speed of light. Hertz used an alternating-current RLC (resistor-inductor-capacitor) circuit that resonated at a known frequency and connected it to a loop of wire. High voltages induced across the gap in the...
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Related Experiment Video
Updated: Jun 21, 2026
06:42
Generation and Coherent Control of Pulsed Quantum Frequency Combs
Published on: June 8, 2018
Proposed flat-topped pulses bursts generation using all-pass multi-cavity structures.
Miguel A Preciado1, Miguel A Muriel
1ETSI Telecomunicacion, Universidad Politecnica de Madrid, 28040 Madrid, Spain. ma.preciado@upm.es
Optics Express
|August 6, 2009
Summary
We present a simple, lossless optical method to create flat-topped intensity pulse bursts from ultrashort pulses. Optimized all-pass optical cavities can generate these desired pulse bursts with high fidelity.
Area of Science:
- Optics and Photonics
- Ultrafast Laser Science
Background:
- Generation of tailored optical pulses is crucial for various scientific applications.
- Existing methods for creating pulse bursts often involve complex setups or losses.
Purpose of the Study:
- To develop a simple and lossless method for generating flat-topped intensity pulse bursts.
- To explore the design of optical cavities for optimal pulse burst generation.
Main Methods:
- Proposed a novel all-pass optical cavity design.
- Investigated solutions for varying numbers of optical cavities and burst pulses.
- Utilized numerical methods to optimize cavity parameters.
Main Results:
- Demonstrated a simple, lossless technique for generating pulse bursts.
- Achieved nearly flat-topped intensity profiles for the generated pulse bursts.
- Identified optimal cavity configurations for different burst parameters.
Conclusions:
- The proposed all-pass optical cavity structures offer an effective way to generate flat-topped pulse bursts.
- This method provides a straightforward approach for producing tailored ultrashort pulse sequences.