Spero IR Microscope

Unrivaled Mid-IR Spectroscopy

QCL-IR Microscopy, by the QCL-IR Experts

In a class of their own, the family of Spero® microscopes represents the world’s first and highest performing wide-field spectroscopic microscopy and imaging platform based on broadly tunable mid-infrared quantum cascade laser (QCL-IR) technology. Get high-quality data at unprecedented speeds.

Forged from Field Experience, Powered by Daylight™

The Spero® microscope is our response to the scientific community’s demand for high-throughput and high-sensitivity, label-free infrared microscopy. Building on Daylight’s expertise in QCL-IR technology, systems, and instrumentation, we pioneered the first wide-field QCL-IR microscope to operate across the important spectral fingerprint region (5-11 µm) in 2014. Since 2014, Daylight has continued to hone and expand the performance of the Spero platform, which is now in its 3rd generation. Spero systems have been successfully installed in over 12 countries and have been field-tested in demanding applications, spanning tissue diagnostics, to cancer research to characterizing novel metamaterials and environmental microplastics.

QCL-IR Microscopy with Spero®

Spero-QT 340

The new Spero-QT 340 system is the third-generation Spero and builds on the successes of its groundbreaking predecessors launched in 2014 and 2017 respectively. Like its predecessors, the Spero-QT 340 provides unrivaled mid-IR spectroscopy, substantially outperforming FTIR microscopes in spatial resolution, speed, and field-of-view while eliminating the need for cryogenic cooling and valuable lab space. Furthermore, it maintains the wide-field, high-resolution attributes of its two predecessors, but with the capability to produce twice the data in one-tenth of the time, while achieving unprecedented signal-to-noise ratios (SNR). The Spero-QT 340 stage can image up to 3 microscope slides, and its larger sample compartment makes it more compatible with microfluidic devices and accessories.

Utilizing Daylight’s unique, patented QCL-IR light engine, Spero-QT 340 is faster than Raman and Photothermal IR microscopes by orders of magnitude while avoiding sample auto-fluorescence and sample degradation by highly focused light sources. Using a proprietary wide-field, low-noise instrument architecture, Spero microscopes enable new data collection modalities such as live, real-time chemical imaging, and user-defined sparse discrete frequency data collection. And the best part? The small desktop footprint (dimensions here in cm) makes Spero suitable for labs with space constraints.

Spero-LT 340

The Spero-LT 340 is the latest addition to the Spero product family. The LT offers the same high-performance speed and resolution as Spero-QT, but offers a lower price-point entry into the Spero family for users who only need transmission, wide-field imaging (a perfect match for tissue imaging and microplastics!). Even better, Spero-LT allows users to upgrade to Spero-QT later if needed.

Please contact Daylight Solutions us to learn more about the different Spero models, and what Spero configuration options are available.

Already an LT owner? Contact us to upgrade your LT today to the top-of-the-line QT model.


Why Quantum Cascade Laser Infrared (QCL-IR) Microscopy?

Quantum cascade lasers provide orders of magnitude higher spectral brightness than incoherent light sources like those used in FT-IR for example. The Spero QCL-IR microscope takes full advantage of this higher spectral brightness, in addition to a set of proprietary compound refractive objective lenses, to illuminate hundreds of thousands of pixels all at once (in parallel). This proprietary approach enables extremely high throughput chemical imaging without sacrificing sensitivity.

QCL-IR-based spectroscopy has its roots in the very well-known and universally accepted Beer-Lambert absorption principle. It is therefore a tool for not only spectrally fingerprinting unknown substances but also for directly quantitating how much of a substance is present with high accuracy. Other techniques like Raman and Photothermal microscopy require special knowledge (e.g. scattering efficiency, thermal diffusion, etc.) of the sample material properties in order to arrive at a quantitative estimate. Furthermore, single point raster scanning IR reflectance instruments require the decoupling of the real and imaginary parts of the refractive index of the sample to perform spectral fingerprinting. This post-processing can be strongly influenced on the particle shape and size making it especially difficult to leverage existing spectral libraries.

What is the difference between QCL-IR Microscopy and FT-IR Microscopy?

FT-IR (Fourier Transform Infrared) has been widely used for microscopy and spectroscopy applications since the late 1960s. As imaging applications have become more demanding for higher-throughput, new technologies have begun to displace FT-IR.

The largest difference between QCL-IR and FT-IR comes down to signal-to-noise ratio (SNR) and time-to-results. FT-IR typically uses incoherent light (such as Globar®)—very similar to an incandescent light bulb. This light emits photons over a broad spectral range and is detected using a scanning interferometer. Since the light source is thermal, high sensitivity detectors and liquid nitrogen are necessary.

Alternatively, QCL-IR microscopy uses all photons at about the same wavelength yielding much higher spectral irradiance. This allows the user to collect a chemical image with an uncooled focal plane array detector (FPA) at 150x faster than a conventional FT-IR microscope at equal SNR. While FT-IR offers a broader spectrum, the success of QCL-IR in a variety of applications has shown that this wider coverage is not essential for many applications.

How does QCL-IR Microscopy work?

A QCL-IR microscope consists of four main sub-systems: (1) a tunable quantum cascade laser or string of QCLs working in concert to cover wider spectral ranges (2) a set of wide-field imaging objective lenses (3) an infrared sensitive focal plane array imager and (4) a precision X,Y,Z stage. At any given instant, only a narrow wavelength (wavenumber) band emits from the QCL. The exact wavelength of that laser is precisely controlled by actuation of an external cavity frequency selective element (a diffraction grating) and is done so seamlessly by the instrument at a rapid tuning speed (msec). The laser light is then transmitted (in the case of transmission imaging) through the sample, then passes through a wide-field infrared objective before it is collected by the focal plane array imager. In the case of the Spero microscope, the imager is a special, broadband and uncooled microbolometer camera operating at video frame rates. The wide-field imaging offers a very large field-of-view (FOV) compared to an FT-IR and enables live, single frequency and rapid hyperspectral imaging of samples.

QCL-IR Microscope Diagram

Lasers and Coherence

Coherence is a fundamental and important property of laser light which is discussed in two: temporal (frequency) and spatial.

Daylight has used its nearly two decades of experience designing and manufacturing thousands of QCL-IR sources and instruments to optimize the Spero’s overall performance and meet the demands of critical applications like tissue imaging and particle analysis. Under the hood, the Spero platform leverages some of Daylight’s most advanced and proprietary coherence control technology to suppress both spatial and temporal coherence effects arising by light-sample interaction while still preserving two main intrinsic advantages of the laser source: high spectral brightness and a well-defined linear polarization state. Preserving optical power is really important in maximizing signal in light starved applications such as flowing liquid analysis or reflectance measurements on weekly reflecting samples. Preserving the polarization state is especially important when conducting polarization dependent spectroscopic studies on novel materials. This technology produces high quality images without any digital post-processing as can be seen in the visible (left) and infrared (right) images of a 50 Euro note below collected by the Spero-QT 340 microscope. Coherence artefacts are not present in these non-processed (raw) images.

QCL-IR Imaging
Visible (Left) vs QCL-IR (Right) reflection mosaic image of a 50 Euro note

ChemVision™ Software for Spero

The Spero systems include ChemVision™ software as part of a complete imaging solution. ChemVision allows users to look at samples at a single frequency in live mode or collect full hyperspectral data cubes in under a minute. Data can be exported into MATLAB and ENVI format for further data processing.

Chemometrics packages are available. Daylight has partnered with Epina ImageLab to create a flexible and open programming interface for enhanced data processing and image analysis.


Features & Benefits

  • Transmission, visible and reflection modes
  • Diffraction limited, high-sensitivity imaging with Focal Plane Array (FPA) detector
  • Multiple, high-NA, large FOV imaging optics (0.7 NA and 0.3 NA)
  • Live, real-time infrared imaging
  • High-throughput hyperspectral imaging enabled by ultra-high brightness QCL technology (>7 M spectral points per second)
  • Large, flexible sample compartment
  • Multiple configuration options including extended wavelength coverage and automated polarization control
  • No cryogenic cooling needed
  • Quick setup means more time for analysis


  • Biomedical imaging of tissues, cells, and fluids
  • Cancer research
  • Pharmaceutical testing of tablets, powders, and liquids
  • Drug discovery: API and excipient optimization and down-selection
  • Protein secondary structure and aggregation testing
  • Real-time reaction monitoring
  • Materials testing and analysis
  • Forensics
  • Chemical detection and identification
  • Microplastic Research


Accessories & Configuration Options

  • Extended Wavelength – Add extended wavelength coverage to 1900-950 cm-1
  • Polarization – Add rotation stage to take polarized images
  • Blue Shifted – Add blue shifted range to 2225-2000 cm-1 and 1800-1200 cm-1

Product Specifications

Specifications  IR Imaging Mode
Wavelength Range Spero-LT Standard Configuration: 1750 cm-1 to 1000 cm-1
Spero-QT Standard Configuration: 1800 cm-1 to 950 cm-1
Customizable between 2300 cm-1 and 800 cm-1
Image Cube Acquisition Time < 40 s (450 absorbance images collected at 2 cm-1 spacing)
Camera Array Size  480 × 480 480 × 480
Image Pixel Size 1.3 µm (0.7 NA) 4.3 µm (0.3 NA)
Diffraction-Limited Spatial Resolution < 5 µm @ λ = 5.5 µm < 12 µm @ λ = 5.5 µm
Numerical Aperture  0.7 0.3
Spectral Resolution  Variable, down to 2 cm-1
Minimum Detectable Signal < 3 mAU per scan
Working Distance  > 8 mm > 25 mm
Field of View (FOV) 650 × 650 µm (0.7 NA) 2 mm x 2 mm (0.3 NA)

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We invented it, and then we made it better. Our Spero microscopes are faster than FTIR and Raman scopes, plus they avoid the need for cryogenic cooling and the complications of autoflorescence. Take a closer look.

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