FTIR (Fourier Transform Infrared Spectroscopy)

What is FTIR?
Why FT-NIR / FT-IR?
FT-NIR: Compact FTIR engine
FT-IR: Type Ⅱ superlattice infrared detector
Solutions for FTIR
Recommended products
Related documents

Compact, high-performance solutions for infrared analysis

Fourier Transform Infrared (FTIR) spectroscopy enables precise identification, quantification, and analysis of materials across a wide range of applications—from medical and chemical analysis to environmental monitoring and materials research.

Hamamatsu provides compact FT-NIR engines and advanced FT-IR detectors to support high-performance spectroscopic systems.

What is FTIR?

FTIR (Fourier Transform Infrared Spectroscopy) measures how a sample absorbs or reflects infrared light to generate a spectral “fingerprint.”

Works with solids, liquids, and gases
Enables qualitative and quantitative analysis
Provides material identification based on spectral data
Widely used in analytical instrumentation

Depending on the wavelength range:

FT-NIR (Near-Infrared): ~1.1 to 2.5 μm
FT-IR (Mid-Infrared): up to ~15 μm

Why FT-NIR / FT-IR?

FTIR is a powerful technique for modern analytical systems:

Non-destructive and rapid measurement
High sensitivity and accuracy
Suitable for compact and portable systems
Broad applicability across industries

FT-NIR: Compact FTIR engine

The Hamamatsu FTIR engine is a palm-sized spectrometer module that integrates a Michelson interferometer and control electronics.

Key technology advantages

High detection performance

To maintain strong signal levels despite miniaturization, Hamamatsu leverages proprietary MEMS technology in the optical interferometer. A precisely engineered movable mirror maximizes the efficient use of reflected light while minimizing optical loss.

By integrating the movable and fixed mirrors into a single MEMS structure and optimizing the actuator design, light spread within the interferometer is reduced—enabling detection performance comparable to conventional stationary systems.

High wavelength reproducibility

Accurate spectral measurement relies on precise control of the optical path. In the FTIR engine, incident light is split, reflected by both movable and fixed mirrors, and recombined to generate interference signals.

The position of the movable mirror is continuously monitored using a photodetector and semiconductor laser, allowing highly reproducible wavelength measurements. This ensures stable and reliable spectral data across measurements.

Compact design with high accuracy

By integrating key optical components into a MEMS-based structure, the FTIR engine achieves significant size reduction without sacrificing performance.

This design improves alignment accuracy between optical elements, reduces mechanical variability, and enhances overall system stability—delivering high-precision measurements in a compact form factor.

Measurement examples

FT-NIR spectroscopy is widely used in the 1.1 to 2.5 μm range, where many materials exhibit unique absorption characteristics that enable precise analysis.

Two primary measurement methods are supported: reflection and transmission.

Reflection measurement (sugar)

In reflection measurements, infrared light reflected from the sample surface is analyzed to obtain spectral information.

Using sugar powder as an example, the FTIR engine was able to accurately capture fine spectral peak patterns. The results closely matched those obtained with a conventional stationary spectrometer, demonstrating that high-precision measurements can be achieved even in a compact system.

See the invisible: Identifying materials with our FT-NIR spectrometer

🎥 Discover Hamamatsu's latest FT-NIR spectrometer (C16511-01), featuring high resolution, high sensitivity, and ultra-fast data acquisition up to 550 fps. Using interferometric technology, it can identify materials that look identical to the human eye—demonstrated by distinguishing real sugar from artificial sweetener.

Transmittance measurement (alcohols)

In transmission measurements, infrared light passing through the sample is analyzed to identify absorption features.

For water and alcoholic beverages, characteristic absorption bands were clearly observed. By analyzing absorbance in the 2.3 μm band, it was possible to estimate alcohol concentration with high accuracy. The estimated values showed strong agreement with known component concentrations, confirming reliable quantitative performance.

FT-IR: Type Ⅱ superlattice infrared detector

For mid-infrared applications, Hamamatsu offers advanced detectors based on Type II superlattice technology.

Advanced superlattice structure

Unlike conventional opto-semiconductors, these detectors utilize a Type II superlattice structure. This consists of ultra-thin layers of InAs and GaSb compounds—each only a few nanometers thick—alternately stacked in more than 2000 layers.

This engineered structure enables precise control of the detector’s optical and electronic properties, allowing for extended wavelength sensitivity and high-performance operation.

Key benefits

Detectable up to 14.5 μm

Excellent output linearity

RoHS-compliant (no mercury or cadmium)

Unlike many conventional mid-infrared detectors that rely on materials such as mercury and cadmium, Hamamatsu’s Type II superlattice infrared detectors are designed using InAs and GaSb compound semiconductors. This material approach eliminates the use of substances restricted by the RoHS Directive, enabling a mercury- and cadmium-free solution. As a result, these detectors support environmentally conscious system design while maintaining high performance in mid-infrared applications.

Manufacturing precision and scalability

Mass production is achieved through Hamamatsu’s proprietary compound semiconductor technology. By precisely controlling the deposition timing and material composition of InAs and GaSb layers—along with optimizing temperature, pressure, and growth conditions—a stable and repeatable manufacturing process has been established.

This enables consistent device performance while supporting scalable production.

Solutions for FTIR

The table below provides a quick guide to selecting the appropriate FT-NIR or FT-IR solution based on your target wavelength range.

Selecting the right FT-NIR/FT-IR solution
Wavelength Range	Solution Type	Recommended Solution
1.1 – 2.5 μm	FT-NIR spectroscopy	FTIR engine (C16511-01)
1.0 – 2.5 μm	Infrared detector	InGaAs photodiodes
1.0 – 3.8 μm	Infrared detector	InAs photodiodes
1.0 – 5.5 μm	Infrared detector	InSb photovoltaic detectors
1.0 – 11 μm	Infrared detector	InAsSb photovoltaic detectors
Up to 14.5 μm	FT-IR spectroscopy	Type II superlattice infrared detector

Recommended products

FTIR engine C16511-01

Utilizing the same powerful interferometer technology of the previous generation, this version of Hamamatsu’s FT-NIR engine is optimized for rapid measurements. Ideal for in-line applications of NIR spectroscopy such as process analytical technology (PAT) and food analysis.

InGaAs PIN photodiodes