India’s Leap into Quantum Sensing: Quantum Diamond Microscope for 3D Magnetic Field Imaging

The development of India’s first indigenous Quantum Diamond Microscope by IIT Bombay’s P-Quest group marks a significant milestone in the country’s quantum-technology journey.

In a landmark development under the National Quantum Mission (NQM) of the Department of Science & Technology (DST), the P-Quest research group at Indian Institute of Technology Bombay (IIT Bombay) has unveiled India’s first fully indigenous Quantum Diamond Microscope (QDM). This innovation—based on nitrogen-vacancy (NV) centres in diamond—is a pioneering platform for dynamic, three-dimensional magnetic-field imaging, and marks the country’s first patented milestone in this high-end quantum-sensing domain.

The announcement was made during the recently concluded Emerging Science Technology and Innovation Conclave 2025 (ESTIC 2025), in the presence of the Hon’ble Union Minister for Science & Technology, Dr Jitendra Singh; the Principal Scientific Adviser to the Government of India, Prof Ajay K. Sood; and the Secretary of DST, Prof Abhay Karandikar, among other senior officials.

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What is the Quantum Diamond Microscope and How it Works

At its heart, the QDM exploits atomic-scale defects—nitrogen atoms adjacent to vacancies—in a diamond lattice. Known as NV centres, these defects exhibit exceptional quantum coherence even at room temperature, enabling extremely sensitive detection of magnetic, electric and thermal variations.

Here’s how the principle works:

• A dense layer of NV centres is engineered near the surface of a diamond chip. (AIP Publishing)

• Under green-laser illumination, these NV centres fluoresce. Their fluorescence is spin-state-dependent, enabling optical readout of the NV spin state via optically detected magnetic resonance (ODMR). (Indian Academy of Sciences)

• When a sample generating stray magnetic fields (for instance, a buried semiconductor current path) is placed in contact with the diamond, the NV layer senses the magnetic field emanating from the sample.

• A wide-field optical microscope images the fluorescence across the NV chip, generating a two-dimensional map of the magnetic field. Advanced processing extends this capability to three-dimensional mapping by appropriate stacking or layered sensing. The technique is analogous to a quantum-sensing version of MRI, but at micro/nanoscale. (AIP Publishing)

The QDM developed at IIT Bombay is tailored for dynamic magnetic-field imaging—i.e., capturing time-varying magnetic patterns rather than just static fields—and configured for 3D imaging of buried current flows, especially in complex multilayer semiconductor chips.

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Why this is a Breakthrough

Several aspects make this development significant:

• First indigenous patent in this domain: India has now achieved a patent in the quantum diamond microscopy & sensing arena, signalling a strategic advance in quantum-metrology capability.

• High-resolution 3D imaging aligned with modern electronics: As semiconductor architectures move to 3D stacking (multi-layer chips, buried interconnects, cryogenic processors, autonomous-systems hardware), conventional diagnostic tools struggle to visualise buried current paths and magnetic signatures. QDM provides a non-destructive technique to map these hidden flows in situ.

• Wide applications beyond semiconductors: Although initially showcased for semiconductor-chip diagnostics, the platform’s sensitivity makes it suitable for neuroscience (imaging magnetic fields from neural networks), materials-science (topological materials, magnetic skyrmions, etc.), battery and energy-storage diagnostics, and geological magnetisation studies.

• Quantum & industry synergy under NQM: Developed under DST’s NQM with academic-industry collaboration (via the P-Quest group at IIT Bombay), this signals how quantum sensing is being translated from lab to productisation in India.

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Development & Strategic Direction

The core research has been led by Professor Kasturi Saha and the P-Quest group (Department of Electrical Engineering, IIT Bombay). Their earlier work on NV-centre sensors for quantum materials is documented in scholarly literature.

Key strategic directions for this development include:

• Engineering a thin diamond layer with high NV density, optimised for wide-field imaging.

• Integration of the diamond sensor with microwave and optical control systems to perform ODMR in ambient conditions (i.e., no cryogenics required).

• Embedding computational imaging techniques—AI/ML-based algorithms—to reconstruct three-dimensional magnetic maps from measured data.

• Collaborating with industry partners (e.g., advanced electronics firms) to adapt the QDM for non-destructive evaluation of 3D stacked chips, including packaging and encapsulated devices.

• Expanding beyond chip diagnostics into neuroscience imaging, where mapping of dynamic magnetic fields (from neural assemblies or in vitro neural networks) may unlock new insights.

A recent press release highlighted a collaboration between IIT Bombay and Tata Consultancy Services (TCS) to develop a “Quantum Diamond Microchip Imager” leveraging this QDM architecture for the semiconductor industry. 

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Implications for Semiconductor & Electronics Industry

The QDM offers specific advantages for the electronics manufacturing and diagnostics sector:

• Non-destructive inspection: Traditional inspection methods (scanning electron microscopy, focused ion beam cross-sectioning, etc.) often require destructive preparation or access to internal layers. QDM allows mapping of current flow and magnetic signatures within encapsulated, multi-layer chips without disassembly.

• Hidden-layer current path visualization: As chips grow vertically (3D ICs, through-silicon vias, heterogeneous integration), detecting defects such as leakage currents, current crowding or unintended coupling becomes increasingly difficult. QDM maps the magnetic fields generated by these currents, enabling diagnosis of faults and yield improvement.

• Quality assurance and failure analysis: In advanced semiconductor manufacturing (FinFET, gate-all-around, cryogenic logic, quantum-computing hardware), subtle defects or parasitics can lead to latent failures. QDM offers a complementary inspection tool for failure analysis labs.

• Cross-industry uses: Beyond chips, QDM can inspect battery cells (current flow in layered electrodes), power devices (magnetic fields in electrical power modules), and MEMS/haptics systems (current loops in micro-actuators).

• Domestic capability: Developing this capability indigenously reduces reliance on overseas tools, enhances technology sovereignty, and aligns with the Make in India and Atmanirbhar initiatives in advanced electronics.

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Potential in Neuroscience, Materials & Earth Sciences

• In neuroscience, the QDM’s ability to image dynamic magnetic fields may allow non-invasive mapping of neural network activity in vitro, or investigation of magnetogenic phenomena in neurobiology. The wide-field, high-sensitivity NV-based imaging platform is well suited for detecting weak neuromagnetic signals.

• In materials science, NV-centre microscopy has been used to probe topological materials, skyrmions, superconductors and thin-film magnetism. The review by Sishir & Saha highlights how NV-centre sensors are used to study quantum materials. (Indian Academy of Sciences)

• In geoscience and magnetisation studies, QDM can map remnant magnetisation in rocks, meteorites or geological samples at high spatial resolution and in a wide field, enabling insights into paleomagnetism or resource detection.

• The integration of AI/ML-based computational imaging promises to convert raw NV-fluorescence data into meaningful 3D magnetic field maps, enabling real-time diagnostics in research or industrial settings.

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Alignment with National Quantum Mission

The National Quantum Mission – launched by the DST – identifies quantum sensing and metrology as a key vertical. The QDM development by IIT Bombay’s P-Quest group is directly aligned with this priority, exemplifying how quantum technologies are transitioning from theory to device to application. The indigenous patent marks an important step in building India’s quantum-technology ecosystem.

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Looking Ahead: Challenges and Roadmap

• Scaling up: Transitioning from lab-prototype to industrial-grade tool will require robust diamond fabrication (high-NV-density layers, uniformity, defect control), system integration (optics, microwave control, thermal stability) and reliability testing.

• Resolution vs field-of-view trade-off: While NV-based wide-field imaging offers rapid mapping, spatial resolution is still constrained (typically several hundred nanometres for wide-field NV microscopy). (AIP Publishing) Enhancing 3D resolution will be a key technical challenge.

• User-friendly software: For mass adoption in industry (chip inspection, battery diagnostics), intuitive software with AI/ML support will be needed to translate raw magnetic-image data into actionable insights.

• Cross-domain calibration: For neuroscience or materials applications, calibration for dynamic, weak magnetic signals and environmental noise suppression will be critical.

• Commercialisation and ecosystem: Developing the tool into a commercial product will require collaborations with instrument-manufacturing companies, service providers, and user communities (semiconductor fabs, research labs, battery makers).

The development of India’s first indigenous Quantum Diamond Microscope by IIT Bombay’s P-Quest group marks a significant milestone in the country’s quantum-technology journey. By enabling high-resolution, dynamic, three-dimensional magnetic‐field imaging at the nanoscale, this innovation opens up new frontiers in semiconductor diagnostics, neuroscience, materials research and geoscience. Aligned with the National Quantum Mission and grounded in robust NV-centre physics, this platform promises to contribute to India’s aspiration of quantum-technology leadership. With upcoming efforts on industrialisation, AI-driven computational imaging and cross-domain deployment, the QDM stands poised to move from laboratory breakthrough to real-world impact.