FAQ for the Monochromator-F/H

General Product Information

What is the Monochromator-F?

The Monochromator-F is a compact, software-controlled fiber-to-fiber monochromator designed for fiber-coupled light sources such as LEDs or laser-pumped plasma light sources. It delivers a tunable monochromatic point light source with high luminance at the output fiber.

What is the Monochromator-H?

The Monochromator‑H is a variant of the Monochromator‑F with a tungsten‑halogen light source directly mounted to the device. Instead of feeding the monochromator through a fiber from an external source, the lamp is integrated and illuminates the input slit internally; the instrument provides a tunable, fiber‑coupled output.

What is difference between the Monochromator-F and H?

The Monochromator‑H integrates the light source for maximum convenience and throughput; the Monochromator‑F is driven by an external, fiber‑coupled source for maximum flexibility in source selection. Both share the same optical concept (grating, order‑sorting filters, shutter), control software, and remote‑control options.

What is special about the Monochromator-F/H?

The Monochromator-F/H features high light throughput, an easily exchangeable optical grating system with magnetic-kinematic holder, an integrated motorized filter wheel, and shutter. An optional high-speed shutter with switching times down to 10 ms is also available. It is optimized for flexible spectral selection across UV, VIS, NIR, and MIR ranges.

What technology does the Monochromator-F/H use?

It uses diffraction gratings mounted on a precision holder to disperse light into its spectral components. Together with off-axis parabolic mirrors for collimation, order sorting filters and a motorized shutter, it provides narrow-bandwidth, tunable monochromatic light output.

What kind of light sources are available for the Monochromator-F?

The Monochromator-F can be connected to any fiber-coupled broadband or narrowband light source. Typical options include high-power LEDs, laser-pumped plasma light sources, deuterium lamps, xenon lamps, and tungsten-halogen lamps. The Monochromator-H variant integrates a stabilized tungsten halogen lamp for stand-alone operation, which is the recommended solution when a tungsten-halogen light source is desired.

Installation

What comes with the Monochromator-F/H delivery?

Monochromator-F/H unit with integrated motorized shutter and order sorting filter wheel. Tungsten-holgen lamp with the Monochromator-H.
12 V / 2.5 A power supply with the Monochromator-F
15 V / 2.5 A power supply with the Monochromator-H
USB/RS232 connection cable
Standard order-sorting filter set (3 filters UV–VIS–NIR)
USB stick with software and manual
Gratings must be specified separately and ordered in addition

How do I install and set up the Monochromator-F/H?

Connect the provided power supply to the Monochromator-F/H.
Connect your light source to the fiber input (SMA).
Connect the output fiber to your detector or application.
Insert the selected grating into the Monochromator-F/H.
Connect the USB cable to a PC or laptop for control.

What safety precautions should I take?

Always block the output beam with a shutter when not in use.
Connect to a properly grounded socket.
Be aware of potential hazardous UV and NIR radiation from connected light sources.
Do not open the device; there are no user-serviceable internal parts.

Computer Interface

How do I control the Monochromator-F?

It is controlled via USB-B connection emulating RS-232. It can be operated using the included GUI, LabVIEW™, Python, or direct ASCII commands.

Is low-level remote control possible?

Yes, direct RS-232 commands and Technosoft TML programming are supported for advanced integration.

What operating systems are supported?

The GUI supports Windows 10 (64-bit) and higher. The Python module and low-level remote control are platform-independent and can run on any operating system that support USB/RS232.

Maintenance and Care

Are there user-serviceable parts inside?

The Monochromator-F does not contain user-serviceable internal parts. Contact the manufacturer for servicing. The tungsten-halogen of the Monochromator-H can be replaced by the user. Replacement requires cool‑down, removal of the lamp block, and careful handling (do not touch the bulb with bare fingers). After replacement, ensure proper seating and secure the holder before powering on.

What is the life time of the tungsten-halogen lamp of the Monochromator-H?

The lifetime of the 13V/20W tungsten halogen lamp inside the Monochromator-H is 3000h. Replacement requires cool‑down, removal of the lamp block, and careful handling (do not touch the bulb with bare fingers). After replacement, ensure proper seating and secure the holder before powering on.

How do I clean the fiber connectors?

Use standard fiber optic cleaning tools and procedures. Avoid touching fiber ends with bare hands.

How do I maintain the gratings?

Handle gratings carefully by their holder. The optical surfaces must not be touched with fingers or tools. Do not attempt to clean the surface except by using clean, dry compressed air. Store gratings in clean containers when not in use.

Special Options

Is there a free-space output version available?

The standard Monochromator-F/H is fiber-coupled. Free-space coupling may be realized using external collimators attached to the output fiber.

Applications

I want to homogeneously illuminate a surface. How can I do this with the Monochromator-F/H?

Homogeneous illumination can be achieved by coupling the monochromated output fiber to a suitable homogenizing optical element. We recommend our homogenizer (fly-eye condenser) as an effective solution.

I need collimated light. How can I realize this with the Monochromator-F/H?

Use a fiber collimator at the output fiber. This provides a collimated beam matched to the fiber’s NA. We offer collimators in different sizes and focal lengths, designed for direct connection to an SMA fiber connector.

Performance

What wavelength range does the Monochromator-F cover?

It covers 190 nm to 5.5 µm, depending on the installed grating.

What wavelength range does the Monochromator-H cover?

It covers 340 nm to 2.0 µm, depending on the installed grating.

What is the achievable bandwidth?

Depending on the grating and fiber core diameter, a bandwidth between 0.7 nm and 28 nm (FWHM) can be achieved.

What is the wavelength reproducibility?

Typical reproducibility is 0.1 nm.

What is the scanning speed?

Scanning speed is typically 100–300 nm/s. As a rule of thumb, the time to switch from one wavelength to another is about 100 ms, including acceleration and deceleration of the grating. For very high scan speeds that cannot be achieved by switching directly from one wavelength to another, a sweep mode can be used. In this mode, the grating does not stop at individual wavelengths but continuously sweeps across the wavelength range at a defined speed.

How efficient is the device?

Efficiency depends on the selected grating and wavelength. Matching the grating blaze to the target spectral range ensures optimal throughput.

What fiber sizes are supported?

Multimode fibers with SMA connectors and core diameters from 200 µm to 1000 µm are supported.

Can I use single-mode fibers with the Monochromator-F?

The Monochromator-F is optimized for multimode fibers with core diameters larger than 200 µm. Below this threshold, efficiency drops significantly. It is possible to use a single-mode fiber with a small core diameter on either the input or the output, but not on both simultaneously.

Operation and Features

How is the wavelength selected?

Wavelength is set via the included Windows software GUI or by ASCII/RS-232 commands. Auto-selection of the appropriate filter and grating is available. A dedicated Python module is also available, allowing easy and direct control of the Monochromator-F via software.

Can gratings be changed by the user?

Yes, the optical grating is mounted in a magnetic-kinematic holder and can be exchanged easily without re-alignment.

What gratings are available?

A wide selection of gratings is available, covering 200–5000 nm with blaze wavelengths optimized for UV, VIS, and NIR/MIR. Line densities from 150 l/mm to 3600 l/mm are offered.

What filters are included?

A motorized filter wheel for up to 5 filters is integrated. A standard set of 3 filters (UV, VIS, NIR), covering the wavelength range 200–2000 nm, is included.

Does the Monochromator-F/H include a shutter?

Yes, it includes a motorized shutter. An optional high-speed shutter (HSS) with 10 ms reproducible switching is also available.

What does the optional High-Speed Shutter provide?

The HSS enables precise, reproducible light blocking and fast exposure control with opening times down to 10 ms, suitable for synchronization with external devices. It supports precise dosimetry for measurement tasks or for the application of actinic light.

What slit widths are available on the Monochromator‑F and H?

Six positions are available. For the Monochromator-F these are: open, 600 µm, 400 µm, 300 µm, 200 µm and 100µm. For the Monochromator-H: 2.0 mm, 1.0 mm, 600 µm, 400 µm, 300 µm, and 200 µm. For best performance, use the same slit width at the input and output.

Can I control the light intensity with the Monochromator-F/H?

The Monochromator-F/H does not include an integrated attenuator. Intensity must be controlled through the connected light source or by the optical setup placed after the Monochromator-F.

Is the Monochromator-F/H calibrated for wavelength?

Yes, it is delivered with wavelength calibration for each grating. Users can refine or recalibrate via the included software.

Selecting the Right Grating

What information do I need to select the right grating?

You need to know:

The target wavelength range (min–max, nm)
The desired spectral bandwidth (FWHM)
The fiber or slit diameter you plan to use
Whether UV performance or stray light suppression is critical
The main working wavelength or range where efficiency is most important

We are happy to assist you in selecting the optimal set of gratings for your application.

Why is the wavelength range important?

The grating must fully cover your working range. Each grating has a defined coverage; if your range exceeds it, multiple gratings are required.

How does the spectral bandwidth (FWHM) affect the choice?

Lower line density gratings provide wider bandwidth, higher line densities provide narrower bandwidth. Your resolution requirement defines the minimum l/mm needed.

What is the influence of fiber or slit diameter?

The fiber or slit width scales the FWHM approximately linearly. Larger fibers/slits increase bandwidth, smaller ones reduce it.

When should I choose a holographic grating?

If your application involves wavelengths below 350 nm or is highly stray-light-sensitive, holographic gratings are preferred as they provide reduced stray light.

How efficient are different gratings?

Gratings with ≤1200 l/mm offer higher efficiency (70–80%). Higher line densities (1800–3600 l/mm) sacrifice efficiency (40–70%) for improved resolution.

Can one grating cover the entire 200–2000 nm range?

No, a single grating cannot provide both high efficiency and optimal resolution across such a wide range. It is generally recommended to use at least two gratings with different blaze wavelengths to cover a broad spectral range effectively.

What is the Minimum Bandwidth (FWHM) achievable for my wavelength range?

The minimum bandwidth is smaller at shorter wavelengths and increases at longer wavelengths. For a fiber core diameter or slit width of 200 µm, the typical values are:

Wavelength < 530 nm: 0.7 nm FWHM with a 3600 l/mm grating
Wavelength < 800 nm: 1.0 nm FWHM with a 2400 l/mm grating
Wavelength < 1000 nm: 1.3 nm FWHM with an 1800 l/mm grating
Wavelength < 1600 nm: 2.0 nm FWHM with a 1200 l/mm grating
Wavelength < 3000 nm: 4.0 nm FWHM with a 600 l/mm grating
Wavelength < 5000 nm: 8.0 nm FWHM with a 300 l/mm grating

What does blaze wavelength mean and how do I select it?

The blaze wavelength is the wavelength where the grating has maximum efficiency. Choose it close to your main working wavelength or near the center of your target range.

How can I maximize throughput in my setup?

Match fiber and slit sizes, select the grating blaze near your working wavelength, and choose the lowest line density that still meets your resolution needs for best efficiency.