Spectroscopy Lab Suite

Explore the relationship between the energy levels in materials and the
spectrum of the emitted light. This package contains four different
programs, each corresponding to an entirely different physical situation,
the only similarity being that in each case the spectrum of emitted light is
presented.

The Gas Lamps module presents the relationship between the discrete energy
levels in a gas and the spectrum of the light emitted by a gas discharge
tube. Choose from a given set of gases or construct the spectrum of a
hypothetical gas. Next, create an energy level diagram for the gas which
would result in the given spectrum.

The LED module extends the idea of the spectrum of the emitted light to from
gas discharge tubes, which have a discrete spectrum resulting from a
discrete set of allowed energy levels, to the continuous spectrum of an LED
which result from an energy band. Observe the relationship between the
energy band gap of an LED and the spectrum of the emitted light for a range
of different LEDs.

The Luminescence module is useful in learning about various luminescence
phenomena. The Fluorescence program explains the working principle of
fluorescent light sources. Adjust the energy of the excited and metastable
state, as well as the energy of the input light. The program displays the
energy of the emitted light. Use the program to understand the relationship
between the emitted light and the energy level in the fluorescing material.

Use the Infrared Detector program to study the principle of the infrared
detector card which is commonly used by TV repair persons to determine
whether the remote control works. Observe that for an IR detector card to
work the electrons have to be pumped up to an intermediate energy level
where they gain additional energy from the IR light before loosing all the
energy to visible light.

The Phosphorescence program is used to understand the mechanism of
phosphorescence and the related electronic transitions. In this program the
user exposes a toothbrush of phosphorescent material to light causing the
electrons to go into an excited state. The toothbrush is then immersed in
liquid nitrogen, which causes the electrons to drop into a metastable state.
Next, the user exposes this toothbrush to a heat lamp. By adjusting the
temperature of the heat lamp, the user can provide sufficient energy to
cause the transition from the metastable to the excited state, from where
the electrons drop back to the ground state emitting light, which is
phosphorescence.

The Lasers module enables the user to understand how lasers work. This
program simulate two different lasers: ruby laser and helium-neon laser. In
either case the user can explore the relationship between spectrum of light
emitted by the laser and the

In the Ruby Laser program the user adjusts the excited and metastable state
energies of the material and turns on the energizing source. If the energy
of the source is greater than that of the excited state a transition appears
from the ground to the excited state. If not, the user receives a message to
increase the energy of the input light and/or decrease the energy of the
excited state. The program then displays the transition to the excited
state, the non-radiative transition to the metastable and finally the
transition from the metastable to the ground state which causes the lasing
action.

In the Helium-Neon Laser program, the user adjusts the various energy levels
in the energy level diagram for the helium and neon atoms. Next the user
provides the energy from the input source which causes a transition to the
excited state of helium. The motion of the helium and neon atoms and their
consequent collision causes a transmission of this energy to the neon atoms.
This causes a transition within the neon which is responsible for the lasing
action.

The correct spectra of both the ruby and helium-neon lasers are displayed in
the respective modes, and the user can adjust the various energy levels in
each case to obtain the desired spectrum.

Thus, in general, this software package is invaluable in understanding the
relationship between energy levels and the spectrum of emitted light in a
variety of different situations.
