Extreme Interferometry

This work was presented at the Gordon Conference on Vibrational Spectroscopy
on Aug 6, 2000 at Salve Regina University, Newport, RI

Table of contents

Extreme Interferometry

Picture of a Vibrational Spectroscopist on the Clearwater River


Conventional FT-IR spectrometer

Desired performance

Precessing Disk Interferometer

Breadboard Instrument

Stress: double-wedge

Top View of Rapid Scan Interferometer Vacuum Box 

3/4 View of Rapid Scan Breadboard Layout

Rapid-scan frequency spectrum

Retardation, velocity and duty cycle

Very-rapid-scan frequency spectrum


Schindler 1

Schindler 2


Tilt-Compensated Interferometer

Nutating Prism Interferometer

Conventional vs Dual-ADC FT-IR Spectrometer

LED Frequency Response

Magnitude vs Phase Response of IR Channel

Magnitude vs Phase Response of Laser Channel

TGS Response over Time

Noise/Artifact Levels

TGS Response Ratios over Time

Vector Resolution

Fourier Transform

FIR Filter

Adaptive Filtering

Data acquisition

Raw ADC output

Raw Infrared Data

Mirror Velocity vs. Time

Filtered Mirror Velocity

Signal Processing

Mirror Position vs. Time

Orthogonality of Components

Synthesized Interferogram

Lomb Periodogram of IR Signal

Lomb Periodogram of IR Signal

Interferogram Noise Level

Theoretical SNR Performance (mid-IR)

Theoretical SNR Performance (NIR)

SNR performance (before vacuum housing)

Single 50 ms Scan; SNR ~500:1

Signal to Noise Ratio 3 ms scans, 4 cm-1 resolution

Spectrum, 3 milliseconds, 4 cm-1

Picture of Chopper Wheel w/ Various Affixed Polymer Samples

Data of 85 Hz Chopper Wheel

5 ms Observation through Wheel

3 ms Scan Through Chopper

Plastic Samples on the Fly 3 ms scans, 4 cm-1 resolution

1,1-Difluoroethane ‘Canned Air’

1,1-Difluoroethane 3 ms scans, 4 cm-1 resolution

Sprayed 1,1-Difluoroethane 3 ms scans, 4 cm-1 resolution



Contact Information

Author: Chris Manning

E-mail: chris@appl-tech.com

Home - Polymer Modulator ™ - Rotating Interferometers - Step-scan Technology
Signal Processing Technology - MAT T-shirts - Bibliography - Links - Private Idaho
Copyright © 1995-2000 All Rights Reserved / webmaster@appl-tech.com