Exploring a Renishaw inVia Confocal Raman Microscope – My Journey as a Technical Lead

As the Technical Lead at TT Instruments, I recently took on the fascinating task of setting up, testing, and listing a Renishaw inVia confocal Raman microscope for sale. This wasn’t simply a case of powering it up and running a few scans, it turned into a personal exploration into the world of Raman spectroscopy. I immersed myself in the underlying principles, the components, and what makes this research-grade microscope such a powerful analytical tool. In this blog, I’ll walk you through what I’ve learnt about Raman scattering (compared to Rayleigh scattering), confocal optics, and the incredible engineering behind each part of the system – from lasers and filters to gratings and detectors. I’ll also share links to some of the SOPs, guides, and resources that helped me along the way.

By the end, you’ll see why this instrument stands out – and if you’re in the market to buy a used Raman spectrometer, this may well be the one for you.

How I Got Into Raman Spectroscopy

Initially, I knew Raman spectroscopy had something to do with laser light and molecular vibrations, but I wanted to really get to grips with how it works and what it’s capable of. Essentially, Raman spectroscopy involves shining monochromatic laser light onto a sample and detecting the light that scatters back. Most of this scattering is elastic; meaning the photons return with the same energy (this is known as Rayleigh scattering). However, a small fraction of the scattered light undergoes an energy shift due to interactions with molecular vibrations – this is Raman scattering.

If a photon loses energy to the molecule, the scattered light appears at a slightly lower frequency – known as Stokes scattering. Conversely, if the photon gains energy from an already excited vibration, it’s anti-Stokes scattering. Because most molecules are in their ground vibrational state at room temperature, Stokes signals are typically much stronger and are what we focus on in Raman spectroscopy.

Each molecule has its own vibrational modes, meaning the energy shifts (measured in wavenumbers, cm⁻¹) are like a molecular fingerprint. The resulting Raman spectrum plots these shifts against intensity, allowing you to identify materials and gain insight into molecular structure.

Why Raman is So Useful

Raman spectroscopy is incredibly versatile – it’s used in:

• Pharmaceuticals (to identify polymorphs or analyse tablet uniformity)
• Materials science (analysing carbon materials, polymers, semiconductors)
• Geology (identifying minerals, inclusions)
• Biology and medicine (non-invasive, label-free chemical analysis)
• Forensics and art conservation (analysing pigments, fibres, residues)

One major advantage is that Raman spectroscopy is non-destructive and generally doesn’t require complex sample preparation. You can often place a sample under the objective lens and acquire meaningful data within seconds.

Confocal Microscopy – What Makes It Special

The “confocal” part of a confocal Raman microscope refers to its ability to focus precisely on a small volume within the sample and reject out-of-focus light. This improves spatial resolution in all three dimensions (X, Y and Z). It allows for optical sectioning, meaning you can construct chemical maps or even 3D representations of your sample.

In the system, confocality is achieved using a pinhole or spatial filter at an intermediate image plane, allowing only in-focus Raman signal through to the spectrometer. Combined with a motorised encoded stage, this enables automated point-by-point scanning across a sample with micron-level precision.

Getting Hands-On: The Components That Make It Work

The Renishaw inVia Raman system we’ve listed is equipped with some impressive and highly capable components. Here's a breakdown:

Dual Laser Sources – 633 nm and 785 nm

The system features two built-in laser sources:

• 633 nm Helium-Neon (HeNe) laser: A low-power red laser known for its excellent stability and coherence. This laser is ideal for samples with good Raman efficiency and moderate fluorescence.
• 785 nm NIR diode laser: A higher-power near-infrared laser that is invaluable when working with samples that fluoresce under visible light. The longer wavelength reduces fluorescence interference, revealing previously hidden Raman peaks.

The ability to switch between lasers is automated via Renishaw’s WiRE software, making it easy to select the optimal wavelength for your specific sample.

Rayleigh Edge Filters

To remove the intense Rayleigh-scattered light (which carries no chemical information), the system uses edge filters tailored for each laser wavelength. These filters block the laser’s exact wavelength while transmitting the inelastically scattered Raman light, even at low wavenumber shifts.

Diffraction Gratings – Spectral Resolution vs. Range

The spectrometer includes:

• 600 lines/mm grating – covers a wide spectral range, ideal for general scans
• 1200 lines/mm grating – higher resolution, for resolving fine spectral features

These are holographic gratings, known for low stray light and high spectral purity. The turret automatically selects the correct grating based on your settings.

Cooled CCD Detector

Raman scattering is extremely weak, so a high-sensitivity CCD detector is crucial. Our system’s CCD is thermoelectrically cooled (to -70°C) to reduce thermal noise, enabling detection of even faint Raman signals. Because it’s an array detector, it captures the entire spectrum in one go, rather than scanning wavelengths sequentially.

Microscope Optics and Objectives

The system uses a Leica DM2700 M stand, configured with:

• Leica N Plan 5× NA 0.12
• Leica N Plan 20× NA 0.40
• Olympus UMPlanFl 20× NA 0.46

Higher magnification objectives can be added, but these lenses already provide excellent resolution and flexibility.

Motorised Encoded Stage

The Renishaw MSC20 motorised XYZ stage allows precise sample movement in sub-micron steps. This is crucial for mapping and repeatable measurements. Positioning can be controlled via software or a dedicated trackball controller.

PC and Software

Included is a modern PC running Renishaw’s WiRE software, the industry standard for Raman data acquisition and analysis. Features include:

• Real-time spectral preview
• Automated laser and grating switching
• Raman mapping and 3D reconstruction
• Baseline correction, peak fitting, and library searches

In our listing, w’ve installed all necessary drivers, calibration files and licenses; it’s ready to go.

What’s Included in the Listing

The full list of what’s included in our Renishaw inVia system is available here.

It comprises:

• Renishaw inVia spectrometer and microscope body
• 785 nm Renishaw HPNIR laser module (300 mW)
• 633 nm HeNe laser module (20 mW)
• Two high-quality diffraction gratings
• Leica microscope with three objectives
• Motorised encoded XYZ stage
• Cooled CCD detector
• Safety interlock, controller units, laser safety goggles
• Calibration samples, cables, manuals and accessories
• Fully set up and tested PC with WiRE software

The system has recently undergone a full factory service and calibration by Renishaw (January 2025), with full documentation included.

Learning Resources and SOPs I Found Helpful

As I was exploring the system, I referenced several authoritative resources to guide my understanding:

• Renishaw Raman Training: Fantastic Training Resources by Renishaw
• Introduction to Raman Spectroscopy (PDF) – Thermo Fisher: Helpful diagrams and explanations
• University of California Irvine, Raman Microscope SOP (PDF): Practical guide on using the inVia
• YouTube walkthrough – Raman setup tutorial: Excellent for visualising laser safety, focusing and calibration

These helped bridge the gap between theoretical understanding and practical use. I’d recommend them to anyone starting out with Raman spectroscopy.

Final Thoughts – Why This System Stands Out

After spending weeks working hands-on with the inVia, I can say this: Raman spectroscopy is amazing, and this instrument does it justice. It’s flexible, automated, accurate, and ready for serious scientific work. Whether you're analysing graphene, pharmaceutical compounds, polymers or geological samples, this setup will serve you exceptionally well.

For those looking for a high-end Raman system without the six-figure price tag of a new model, this is a rare opportunity. It’s in excellent condition, recently serviced, and comes with everything needed to get started.

View the Listing

Check out the full product page here: Calibrated Renishaw inVia Research-Grade Confocal Raman Microscope & Spectrometer

If you have any questions, feel free to reach out. We’d be delighted to help you find the right system for your needs.