In most experiments, the precision with which measurements can be made is restricted by random fluctuations, usually called noise. One way of dealing with electrical noise is to use careful shielding. Another way is to use frequency filtering techniques. In this experiment, you improve the sensitivity of magnetic field measurements using the Hall effect probe by going from DC amplification to tuned amplifiers and lock-in amplifier techniques. The experiment does not have to be confined to investigating Hall effect probes.

This experiment is an investigation of blackbody radiation. Light emitted from an oven is detected using a prism spectrometer and thermopile detector. The signal-to-noise is greatly improved using an optical chopper and lock-in amplifier. The confirmation of the Stefan-Boltzmann Law is one of the standard experiments that can be done. You can also try to confirm the Planck Law, or look at the absorption spectrum of semiconductors (or other materials) using your newly calibrated spectrometer.

An optical bench and a variety of lenses and filters allow you to test matrix methods for locating images in multiple lens systems. You can also use the CCD camera to determine image sharpness.

In this experiment, the Doppler effect using electromagnetic radiation (microwaves) is studied. In particular, the principle of the heterodyne Doppler technique is used to measure the velocity of a car moving on a track, which is precisely the idea behind the police radar trap! The frequency from the transmitter is mixed with the reflected frequency from a moving car, and a frequency difference is observed on an oscilloscope. Another way of analyzing the system is to think of two beams interfering and measuring the beat frequency.

Fiber-optic networks are now prevalent in telecommunications. Compared to copper cables, optical fiber systems have many orders of magnitude greater bandwidth and therefore can carry much more information. They are also less sensitive to external interference and need less energy to transmit signals over large distances. This lab is an introduction to optical fibers and fiber-optic communications.

A long, dark, stove-pipe assembly and a HeNe laser source allow you to explore near-field diffraction of light from various objects. The diffraction patterns can be photographed with the CCD camera or intensity profiles can be taken using the linear CCD array. The intensity profiles can then be compared to theory.

A darkroom, optical table, mirrors, lenses, filters, laser source and a (limited) supply of photographic plates allow you to make holograms of small 3-D objects. Different types of holograms can be tried: transmission, reflection, interference, multi-exposure, etc.

In this experiment, you will examine a Michelson interferometer and a Fabry-Perot interferometer. In particular, you can compare how well each type of interferometer can resolve very small differences in wavelength - first starting with a sodium doublet and then onto more difficult topics such as hyperfine structure of mercury. The Fabry-Perot interferometer can be used in two ways: moveable-mirror and fixed-mirror configurations. A good working knowledge of the Fabry-Perot interferometer is needed in performing the Zeeman Effect experiment.

As a follow-up to experiments with the Fabry-Perot interferometer, you may wish to use it to measure the Zeeman splitting of the mercury green line. The interferometer must first be calibrated using a known wavelength to determine its gear ratio.

Sonoluminescence is the production of light from sound waves. In this experiment, you investigate the nature of light emitted from the rapid collapse of cavitation bubbles generated by intense sound waves in a liquid. The mechanism by which the light is generated is not completely understood, and is an area of active research by several groups around the world. In fact, sonoluminescence was recently observed for the first time in nature from the cavitation bubbles produced when shrimp ÒsnapÓ up their food (Lohse et al., Nature 413, 477 (2001); Oct. 4 issue).

A scintillation counter sensitive to gamma rays and instrumentation capable of discriminating between gamma rays of different energies is used to plot gamma ray spectra. After setting up the equipment and doing some initial calibrations with known radioactive sources, you can study unknown sources, gamma ray absorption characteristics, Compton edge, and the energy resolution of the equipment.

The classical theory of Electromagnetism predicts that an electromagnetic wave (light) travelling from a high index to low index material will penetrate into the barrier even at angles greater than the critical angle for total internal reflection. If the barrier consists of a thin gap, some of the light will pass through the gap in what is called frustrated total internal reflection. This phenomenon can also be interpreted in terms of quantum mechanics as an example of quantum tunneling across a potential barrier. In this experiment, you will be given a laser and a Newton's rings apparatus to provide a variable thickness gap. You can then compare the transmission and reflection amplitudes that result with the predictions of Electromagnetism and Quantum Mechanics.

We usually think of Fourier transforms in an electrical sense, such as the frequency components which make up a square wave, and what happens to such wave forms when either high or low frequency components are removed by filtering. Optical images can have fine detail and coarser elements, equivalent to high and low frequencies in electrical signals, which can be filtered using diffraction techniques. This experiment allows you to explore the techniques involved in Fourier optics and image processing. The CCD camera is used to record your images.

Interference and diffraction are explained as wave aspects of light. With a cooled photomultiplier tube, it is relatively easy to detect individual visible light photons. It is also possible to create sufficiently dim light conditions such that no more than one photon would be present inside the apparatus at a time. If single photons are aimed at a double slit, will a double-slit diffraction pattern still be seen? Welcome to the strange world of quantum mechanics!

This experiment involves the investigation of sound waves in a narrow 2D box. In particular, you will determine the various resonant modes and compare these to theoretical predictions. A small transmitter (microphone) is used to emit sound waves and a second microphone (detector) is used to measure the locations of the resonant peaks on an X-Y grid.

The Peltier cell works on the principle of the thermoelectric effect "in reverse". By forcing a known current (emf) through a Peltier cell, a specific temperature can be attained. The emphasis of this lab is on the thermodynamics of the Peltier cell.

Acoustic waves in liquids cause density changes with spacing determined by the frequency and the speed of the sound wave. For ultrasonic waves with frequencies in the MHz range, the spacing between the high and low density regions are similar to the spacing used in diffraction gratings. Since these density changes in liquids will cause changes in the index of refraction of the liquid, it can be shown that laser light passed through the excited liquid will be diffracted much as if it had passed through a grating. Raman-Nath diffraction is slightly different from diffraction from a ruled grating, and you should try to investigate the difference. The experiment can serve as an indirect method of measuring the velocity of sound in various liquids and solutions.

Today's technology, be it x-rays, computer chips, light bulbs, or nuclear accelerators, would be impossible without the routine capability to achieve a good vacuum. The purpose of this experiment is for you to gain some experience with basic vacuum techniques and to make measurements which require a vacuum. The pumping station comes complete with gauges and is set up with a bell jar for evaporation of thin metal films. A spectrometer is available for measuring the optical absorption of thin films over the wavelength range from 350 to 1000 nm.

Theses are table-top units operating at either 20 or 30 kV with copper target anodes. A wide variety of X-ray measurements can be done, such as Bragg diffraction from cubic crystals, absorption and Moseley's law, radiography, and a rough determination of Planck's constant. In a sense, two approaches can be taken. One is to assume the basic properties of X-rays and use them to do crystallography. The other approach is to make use of crystallography to create monochromatic X-rays, and then investigate the properties of X-rays of different wavelengths.

You will be able to image atoms with this microscope.

Learn the basic principles of pulsed NMR. (The same principles apply to MRI Ð magnetic resonance imaging Ð used in hospitals.)

- digital sampling oscilloscopes (60 MHz and 300 MHz bandwidths)Ð can print out waveforms
- computers for data acquisition
- Nikon CCD camera for image acquisition and download
- CCD line scan camera for Fresnel diffraction lab - Hall probe for measuring small and large magnetic fields
- lock-in amplifier, chopper, and detector for blackbody radiation lab - optical power meter