Redback RS40k User manual

RS40k Echelle Spectrometer
User Manual
Version 1.5 - July 7, 2023

© Redback Systems Pty Ltd. All rights reserved. No part of this publication may be reproduced
by any means without the written permission of Redback Systems.
Thorlabs is a registered trademark of Thorlabs Inc in the United States and/or other countries.
Windows is a registered trademark of Microsoft Corporation in the United States and/or other
countries.
The information in this publication is believed to be accurate as of the publication release date.
However, Redback Systems does not assume any responsibility for any consequences including
any damages resulting from the use thereof. The information contained herein is subject to
change without notice. Revision of this publication may be issued to incorporate such change.
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Table of Contents
1. Introduction 2
2. Requirements 2
3. Warnings 4
4. Safety Precautions 4
4.1 General Handling 4
4.2 Fibre Installation 5
5. Installation 5
5.1 Contents of Shipment 5
5.2 Spectrometer Interfaces 6
5.3 Optical Fibre 8
5.3.1 Cleaning Optical Fibre Connectors 9
6. Software 10
6.1 Updates + Downloads 10
6.1.1 Check your software version 10
6.2 Software Installation 10
6.3 Wavelength Calibration 11
6.4 User Interface 13
6.4.1 Toolbar Actions 14
6.4.2 Spectrum Acquisition 16
6.4.3 Saving data 16
6.4.4 Regions of interest (ROIs) 17
6.4.5 Dark Screen 17
6.4.6 Periodic Acquire 17
6.4.7 Dark Calibration 18
6.4.8 Flat-Field Calibration 20
6.5 Python API 22
6.6 Troubleshooting 22
6.6.1 Wavelength offset correction 22
6.5.1 High detector humidity warning 23
7. Device properties 25
7.1 Optical Parameters 25
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7.2 Device Parameters 26
7.3 Device Dimensions 26
8. Technical Support 27
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1. Introduction
Thank you for purchasing a Redback Systems product. This manual provides you with
directions on the device installation and operation as well as a brief introduction to the
RedSolve software. Please read the following instructions carefully.
NOTE: Please read this manual carefully before installing and operating your new
RS40k spectrometer. It is important to understand and follow all safety, installation,
operation, and maintenance procedures as stated to ensure proper functionality.
2. Requirements
To ensure your computer can operate the device software and drivers, please read the
hardware and software system requirements below. Note that at this time only the
Windows operating system is supported. In addition to hardware requirements, an
internet connection is required for downloading the device driver, software and manual.
Minimum hardware and software requirements:
●Operating System: Windows 10 (64 bit)
●Processor: Intel Core i5 or AMD Ryzen 5
●USB 2.0 port
●RAM: 8.0 GB
●HDD: 256 GB internal hard drive
Recommended hardware and software requirements:
●Operating System: Windows 10 (64 bit)
●Processor: Intel Core i7 or AMD Ryzen 7
●USB 3.0 high speed port (preferred)
●RAM: 16.0 GB RAM
●HDD: 1TB internal SSD hard drive
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3. Warnings
●Your Redback Systems spectrometer is a precision optical instrument. Always
handle it with the level of care appropriate for such instruments.
●There are no user serviceable parts inside the spectrometer housing or inside the
camera. Subsequently, both components MUST NOT be opened.
●Care should be taken such that the camera does not overheat. The camera’s air
vents must not be blocked.
●Your Redback Systems spectrometer does not contain a shutter. Please avoid
illuminating the detector with high-power lasers.
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4. Safety Precautions
4.1 General Handling
●Handle the spectrometer with care.
●Make sure the spectrometer is placed on a flat surface with its red lid at the top.
●Do not operate in damp or wet conditions with RH >70%.
●Do not use the spectrometer in an outdoor environment.
●Do not disassemble the spectrometer or attempt to modify or repair it.
●Do not subject the spectrometer to mechanical shock or vibration.
●Do not cover the cooled detector.
●Do not operate the spectrometer in explosive environments.
●Only use the electrical cables provided.
●Avoid static electricity.
4.2 Fibre Installation
●Take care when installing the optical fibre.
●Only use FC/PC fibre connectors as specified in Section 5.3 of this manual.
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5. Installation
5.1 Contents of Shipment
Please inspect the device mechanically and unpack the contents in a clean, dry, and
EDS-free area. Verify that you have received the following items with the package:
●RS40k spectrometer in Pelican 1520 storage case
●12V/5A power supply and cable
●USB 3.0 cable
●S405-XP and 780HP single-mode fibres with FC/PC to FC/APC connectors
●USB flash drive with unique wavelength calibration file
●Desiccant container filled with silica gel
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5.2 Spectrometer Interfaces
NOTE: Do not connect the RS40k echelle spectrometer to any PC prior to installing
the software application and device drivers. Please use the included USB 3.0 cable to
connect the detector with your PC or laptop.
The spectrometer interfaces are shown in Figure 1. The device has four mounting slots
which are machined into the aluminium housing. Off-the-shelf mounting hardware (e.g.
Thorlabs CL5A) can be used to secure the device onto the optical table. Make sure not
to overtighten the screws as this could result in permanent deformation of the rubber
feet and can also exert stress onto the housing which can negatively affect the
performance of the device.
Figure 1: RS40k spectrometer ports and interfaces: (1) fibre input, (2) mounting slots,
(3) 12V power, (4) USB 3.0 interface, and (5) Trigger IN/OUT. Note, the Trigger IN/OUT
interface are optional and not activated by default.
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5.3 Optical Fibre
The RS40k is specifically designed to work seamlessly with single-mode fibres that are
equipped with FC/PC connectors. When you receive the device, it will come with two
hybrid single-mode fibres (SMFs) that are suitable for your spectrometer's wavelength
range. In Figure 2, you can see a depiction of commonly utilised single-mode fibres,
which effectively cover the wavelength range of your spectrometer. The solid bar shows
the transmission range given in the supplier’s datasheet. The measured range can vary
from fibre to fibre and often exceeds the theoretical limit (see hatched area).
Figure 2: Selection of standard SMFs compatible with the RS40k wavelength range. The
hatched area indicates the measured fibre transmission, exceeding the theoretical range.
Butt coupling FC/APC fibres to FC/PC fibres may result in light loss of up to 50%. We
recommend using hybrid patch cables with FC/PC and FC/APC connectors if your
experiment is based on APC fibres. Your RS40k package includes a set of hybrid patch
cables (Thorlabs S405-XP and Thorlabs 780HP) which cover the 420-950 nm range.
NOTE: If your system requires fibres with FC/APC connectors please use the included
hybrid patch cables to adapt your fibre system to the RS40k spectrometer.
Testing of the device has revealed that light leakage through coloured furcation tubes is
able to be detected in the NIR range of the spectrum. Therefore, for best results, we
recommend using fibres embedded in black or metal furcation tubes only. Alternatively,
the device should be operated with the room lights switched off.
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5.3.1 Cleaning Optical Fibre Connectors
The optical fibre must be thoroughly cleaned before plugging into the device. Please
ensure that the fibre tip is free of scratches, dust, or any kind of dirt to achieve the best
possible performance. We recommend using a fibre inspection microscope to regularly
inspect the fibre-end faces at high magnification. Clean the connector ends in case dust
and dirt has settled on the fibre tip. Figure 3 shows a successfully cleaned fibre surface
for reference (see right image).
Figure 3: Microscope images of a dirty (left) and clean (right) fibre end.
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6. Software
6.1 Updates + Downloads
Each spectrometer is shipped with the current version of RedSolve at production date.
The latest version of the RedSolve can be downloaded from our website:
www.redback.systems/downloads.
Prior to installing any updated software, you should first disconnect the spectrometer
from the computer and uninstall the current software completely from the computer.
6.1.1 Check your software version
You can check what version of the RedSolve software you have installed, under the
Options file menu click About (Figure 4).
Figure 4: The About dialog is accessible from the Help menu.
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6.2 Software Installation
1. Prior to commencing the installation process, terminate and exit any programs
currently running on your computer.
2. Ensure the spectrometer is not connected to the computer.
3. Install the hardware driver from your USB drive
4. On the install options page you only need to select the driver, as shown below:
Figure 5: The device installation wizard. Select Drivers only and proceed with the installation.
5. Download and run the latest RedSolve Setup [version].exe file from our website
and follow the prompts presented by the install wizard.
6. After successfully installing the software, connect the RS40k spectrometer to
your computer via the provided USB 3.0 cable.
7. Run RedSolve, then open the Settings dialog from the Options menu. Load the
calibration file from the provided USB flash drive.
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6.3 Wavelength Calibration
Each spectrometer is shipped with a unique calibration file. As part of the spectrometer
installation process you must first load your calibration data from the USB drive. If no
calibration file has been previously used, you will be prompted by the below dialogue.
Once the calibration file is loaded you can use RedSolve to acquire data.
Figure 6: A warning to load the calibration file is shown on startup.
Clicking OK will take you directly to the settings window where you can load the
included calibration file. You must click OK or Apply in the settings window to activate
the calibration file. The Settings dialog can also be accessed from the Options menu.
Figure 7: Load your calibration file from the USB drive into RedSolve.
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6.4 User Interface
Below (Figure 8) is an annotated screenshot of the RedSolve user interface.
Figure 8: The RedSolve main window.
The annotated sections of the user interface are:
1. Measurement toolbar.
2. Data visualisation toolbar.
3. Full-spectrum thumbnail plot. This panel will always display the full data range
acquired.
4. Status bar.
5. Regions of Interest (ROIs). A region of interest (ROI) can be created to inspect a
subset of the collected data. Multiple ROI panels can be created.
6. Detector temperature and relative humidity (for cooled detectors only).
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6.4.1 Toolbar Actions
All action buttons and menu selections contain mouseover text where appropriate. The
following table briefly describes the most commonly used actions.
Acquire
Exposes the detector for the set exposure
duration and converts the image into data.
Exposure time
The detector exposure time in seconds.
Live view
Refreshes the spectrum as quickly as possible.
The refresh rate is limited by the exposure time
and the data processing time. No data is recorded
from Live view.
Save
Saves the spectrum data to a *.csv file. The user
will be prompted to confirm the saving directory
and filename.
Load
Load previously saved data for further exploration
or processing.
New ROI
Creates a new region of interest (ROI).
Set Dark
Set the current data as a dark frame to allow dark
subtraction.
Set Flat
Set the current data as a spectrally flat frame to
allow amplitude compensation for the echelle
blaze angle modulation.
Subtract Dark
Subtract the current dark frame from the
measured data. Can be toggled on and off as
desired without reacquiring data.
Show Flattened
Apply the flat-fielding compensation for the
echelle blaze angle modulation. Useful when
visualising broader spectral features.
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6.4.2 Spectrum Acquisition
The detector chip provided in your Redback Systems spectrometer may have higher
sensitivity than other comparable spectrometers. For this reason, to avoid saturation of
the detector we recommend starting your measurements with shorter exposure times,
and incrementing the exposure time as required. The dashed line in the overview plot
shows the maximum intensity before saturation. Breaching the exposure limit can
cause light bleeding into adjacent orders which generates false signals in the spectrum.
Please stay below the limit in your region of interest to avoid distorted data.
NOTE: Stay below the saturation limit in your region of interest to avoid distorted data
and artificially created peaks from light bleeding into adjacent orders.
6.4.3 Saving data
To save your data, click on the Save button and select the desired file directory. The
complete data array will be saved in *.csv file format. Relevant metadata (e.g. exposure
time, acquisition date, etc.) will be saved in the file header. A presentation-ready image
showing a screenshot of the data is also saved (see example in Figure 9).
Figure 9: Example of a presentation-ready image.
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6.4.4 Regions of interest (ROIs)
To give users instant access to data analysis, one can create multiple regions of interest
(ROIs) in the main window. Many ROIs can be created. If the number of ROIs opened
exceeds the available screen real-estate, then new ROI windows will be created as tabs.
6.4.5 Dark Screen
Selecting the Dark screen option from the View menu changes the background colour
from light to dark for low-light experiments. Icons and toolbar buttons are not affected
by the dark screen mode (Figure 10).
Figure 10: RedSolve dark screen mode.
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6.4.6 Periodic Acquire
The Periodic Acquire function will automatically acquire data at defined intervals, and
for either a fixed or infinite number of repetitions. Additionally, the user can toggle if they
would like to save the data from each acquisition.
Figure 11: The Periodic Acquire menu, located within the Tools menu.
Figure 11 shows the Periodic Acquire menu. When the Auto-refresh button is engaged
the measurement will run with the input Interval and Repeats parameters. Setting
Repeats to “0” will continue the measurement series indefinitely. Toggling Save on ↻will
save the acquired data after each acquisition.
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6.4.7 Dark Calibration
Modern CMOS detectors offer a number of advantages compared to more traditional
CCD detectors, including increased sensitivity over a wider wavelength range and faster
detector read-out. Similarly to CCD detectors, their performance, however, strongly
depends on temperature. As a consequence, some background counts from thermal
electrons are typically recorded, even when no light hits the detector chip. First-order
data reduction must be applied to all recorded images in order to remove noise
associated with the CMOS detector.
The RS40k has a Peltier-cooled scientific CMOS sensor to minimise this effect. The
cooler is activated in the device software RedSolve. The lowest temperature that can be
reached is 40°C below ambient. We recommend operating the detector at about -10°C
(set by default) to achieve the best performance and sensitivity. The sensor temperature
and detector chamber humidity is always displayed in the lower right corner of the
software interface (Figure 12).
Figure 12: The sensor temperature is shown in the lower right corner of the software interface.
If the sensor temperature is not within ±1°C of the set temperature it will be highlighted in red.
To remind the user, a warning will be displayed if an acquisition is attempted when the
sensor has not yet cooled to the set point (Figure 13).
Figure 13: The user will be cautioned if the sensor temperature is not within ±1°C of the set
temperature. Note, the default setting is -10°C.
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