The debate about whether quantum computing will happen is over. Our latest Quantum Technology Monitor shows that more than 300 companies worldwide are actively adopting quantum computing, and that in 2025, global investment in quantum start-ups reached $12.6 billion—more than six times as much as in 2024. With this momentum, we predict that the global “internal quantum market”—or the market for the technology itself, including hardware, software, and services—could reach $60 billion to $100 billion by 2035. The business interest and capital are here. The science is advancing rapidly. Now, to achieve quantum scaling, the remaining problems to solve are at the system level: error correction, quantum control, and supply chain bottlenecks.
One component sits at the center of scaling constraints: the single-photon detector (SPD). Though SPDs are rarely in the headlines, they are critical in the race to build quantum computing hardware. For several of the most promising quantum computing architectures, SPDs are as foundational as the qubit itself.
What single-photon detectors do, and why they matter now
SPDs register and time-stamp individual photons—the smallest unit of light—pushing detection sensitivity to the limits that physics allows. SPDs are a specialized category of photodetectors used across cameras, imaging, and telecommunications, distinguished by their extremely high sensitivity and response times. SPDs already underpin technologies that many people encounter: positron emission tomography (PET) scanners in hospitals, LiDAR in autonomous vehicles, and flow cytometers in biomedical research labs.
The SPD landscape spans three generations. Photomultiplier tubes (PMTs), the original SPD technology dating back to the 1930s, remain a workhorse in biomedical instrumentation and industrial sensing. Based on our analysis, the PMT market is worth an estimated $400 million to $600 million worldwide in 2026, growing modestly and gradually being displaced by solid-state alternatives. The second generation—single-photon avalanche diodes (SPADs) and silicon photomultipliers (SiPMs)—started being used to manufacture complementary metal oxide semiconductors (CMOS) in the 2000s. Based on our analysis, SPADs and SiPMs will represent a $1.2 billion to $1.6 billion global market in 2026, growing to $3 billion to $6 billion by 2035. The main growth drivers of this market are consumer electronics depth sensing, automotive LiDAR, SiPMs displacing PMT-based PET scanners, and quantum key distribution (QKD) hardware in quantum communication. Competitive advantage in this segment favors sophisticated engineering companies that have CMOS manufacturing capabilities and existing design relationships.
The third generation of SPDs—superconducting single-photon detectors (SSPDs)—could be the key to building quantum computing hardware at scale. First demonstrated in the early 2000s, SSPDs achieve detection efficiency, noise levels, and timing precision that solid-state detectors cannot yet match, particularly at telecom and infrared wavelengths. SSPDs are widely recognized not only as critical enablers of quantum computing hardware but also for their potential to unlock the next generation of biomedical and defense sensing. The trade-off is operational complexity: SSPDs require cryogenic cooling, typically to around 1–4 Kelvin, which adds cost and system integration challenges. Our analysis finds that the SSPD market is worth $30 million to $50 million worldwide in 2026—primarily based on spending from research labs and government programs.
SSPD as a strategic enabler of quantum hardware
To understand why SSPDs matter for quantum, it helps to look at the hardware architectures coming closest to commercial viability. SSPDs are embedded in the optical control and interconnect layer of the leading hardware modalities for quantum computing and communication:
- Photonic quantum computing: In photonic quantum computers, quantum information is encoded in particles of light called photons, rather than in standard qubits. Computation depends on detecting individual photons with near-perfect efficiency and near-zero error rates. Thus, detection accuracy and timing directly determine how well and how quickly entangled states can be created and measured. Photonic computing companies are working to improve these two capabilities within SSPDs. PsiQuantum, a photonic quantum computing player, has made foundry-scale fabrication of SSPDs a core part of its approach to scaling quantum computers—treating the detector not as a component to procure but as a strategic asset to improve.1
- Neutral atom and trapped-ion quantum computing: These two quantum computing hardware modalities rely on highly sensitive photon detectors to measure qubit states. A key measure of detector performance is detection efficiency and timing precision; the more efficient and faster the detector, the less time is required to confidently measure a qubit’s state. This rapid measurement and readout is critical for reducing qubit errors as systems scale. IonQ’s 2025 acquisition of ID Quantique, a leader in quantum detection systems, was accompanied by an explicit statement that SPD systems are integral to scalable quantum computers.
- Superconducting quantum computing: Because superconducting qubits operate on microwave frequencies, individual processors do not require SSPDs. However, scaling these systems requires quantum communication. Multiple quantum processors are networked together in a process called modular quantum interconnection, which unifies separate processors and allows independent hardware modules to function together as one computer. This requires converting microwave signals into optical photons for fiber transmission, making SSPDs a critical enabler for quantum communication.
- Quantum communication: Quantum communication, including interconnections between modular quantum computing processors and the global quantum internet, requires distributing entanglement across distance. SSPD determines link fidelity and entanglement generation rates—the two metrics that define how fast a quantum network can operate and how large the network can scale. SSPD can be used for quantum communication regardless of the underlying quantum computing hardware modality.
Beyond quantum computing, SSPD’s infrared sensitivity is opening two additional high-value markets: biomedical imaging and aerospace. These are additive demand tailwinds for SPDs that exist independently of quantum’s trajectory. In biomedical imaging, SSPD enables deeper tissue penetration, lower phototoxicity, and faster tracking of biological dynamics—capabilities that conventional SPDs cannot deliver. Real-world adoption is already underway: SSPD is being tested for cancer diagnosis, noninvasive intravital imaging, and in diffuse correlation spectroscopy (DCS) for noninvasive bedside neuromonitoring of cerebral blood flow.2
In aerospace and defense, a compelling proof point for SSPDs arrived in April 2026: During the Artemis II mission, SSPDs used at the Australian National University’s Quantum Optical Ground Station near Canberra received laser communications from the Orion spacecraft in the lunar vicinity. The station sustained dual-stream video for more than 15.5 hours and downlinked at the O2O terminal’s maximum 260 Mbps—orders of magnitude above Apollo-era radio rates.3 The detector vendor reports that the ground station’s superconducting nanowire single-photon detectors, cooled to near-absolute-zero temperatures, captured photons at over 90 percent efficiency.4 The Artemis II deployment demonstrated that mission-critical performance requirements can justify the cost and complexity of cryogenic SSPD operation.
The market opportunity for SSPDs
Our analysis predicts that the SSPD market size will reach $1 billion to $4 billion worldwide by 2035—a range that reflects uncertainty in the rate of quantum adoption, not uncertainty about whether demand exists. Quantum technology is the biggest demand driver. Quantum computing and communication together could drive $300 million to $2.5 billion in SSPD demand worldwide by 2035, with the market size determined by which computing hardware modalities achieve fault tolerance first and at what scale. (If the superconducting quantum computer platform wins the hardware race, then the need for SSPD could be lower than if neutral atom, photonic, or trapped ion platforms prevail, because superconducting qubits don’t use optical photons to carry quantum information.) By 2035, biomedical imaging could add $300 million to $900 million in global SSPD demand, as the technology penetrates high-value clinical and research applications. Aerospace and defense sensing could contribute an additional $100 million to $700 million in SSPD demand, where mission-critical performance requirements—as demonstrated by Artemis II—can justify the complexity premium. An additional $200 million in SSPD demand could come from sustained research and development demand.
Despite the critical importance of SSPDs for quantum hardware scaling, the production infrastructure and engineering maturity for SSPDs are nowhere near ready for that demand. Our analysis finds that the global market for SSPDs sits at $30 million to $50 million today—primarily driven by demand from private and public research labs experimenting with the technology. To scale effectively, today’s leading quantum hardware architectures would require SSPD at manufacturing volumes orders of magnitude higher than today. Closing that gap requires sustained investment in the SSPD supply base—across system integration, performance optimization, and scaled manufacturing facilities.
The investment window for SSPD is now
There are three main players in the quantum technology ecosystem that could provide meaningful funding for SSPD development: quantum computing companies building next-gen hardware, deep-tech investors looking to win this space, and component companies manufacturing SSPDs. Each of these groups has a huge opportunity to capitalize on the emerging multibillion-dollar SSPD market and risks losing ground if they do not invest now.
- Quantum computing companies: The current period presents a unique opportunity for quantum hardware companies to think beyond qubits and map out the critical enabling systems and components needed to deliver performance at scale over the next five years. For photonic, trapped-ion, neutral-atom, and quantum communication architectures, system-level photon detection performance and SSPD supply constraints will directly impact scaling timelines. The choice is either vertical integration, as PsiQuantum has chosen, or deep partnership with an SSPD provider. The risk of not acting now is a potential delay in the timeline to manufacture fault-tolerant quantum computers at scale. Building a scaled SSPD supply base and subsequent system integration will require years of sustained investment. Companies that wait will also find themselves navigating a more consolidated SSPD supplier market with less room to gain preferential access.
- Deep-tech investors: No dominant commercial SSPD player has emerged, presenting an opportunity for venture capital and corporate investors to back the future winning horses. The current window allows investors to back category-defining companies before preferred SSPD vendors are locked in by the major quantum computing players. SSPDs also offer an alternative investment avenue for gaining exposure to the strong growth expected in the quantum computing hardware market with less risk of “betting on one hardware horse”—since SSPDs work with multiple quantum hardware modalities, whereas qubits are tied to one kind. There’s an additional upside from the biomedical and defense markets outside of quantum.
- SSPD component makers: The current window offers a unique opportunity for SSPD component companies to position themselves as systems partners to quantum technology companies, rather than just suppliers, before quantum architecture choices become locked. The companies that forge deep integration partnerships early will have structural advantages over pure-play component vendors. Partnerships with quantum technology companies also provide a critical path to the corporate investment needed to accelerate the scaling and integration challenges currently constraining SSPD adoption. Component companies can also hedge quantum uncertainty by advancing use cases in biomedical imaging and aerospace and defense—capturing multiple funding sources and diversifying the end-market mix for their products.
SPDs are critical enablers for moving quantum computing from experimentation to wide-scale deployment. The companies and investors that invest in SPDs’ potential today will become the main players in scaling quantum hardware. They will capture structural positions that are difficult to displace once the quantum ecosystem matures. The window to act is now.
Henning Soller is a partner in McKinsey’s Frankfurt office, Martina Gschwendtner is an associate partner in the Munich office, and Ming Xu is a consultant in the Connecticut office.
The authors wish to thank Professor Hong Tang at Yale University for his contributions to this article.
1. “PsiQuantum and GlobalFoundries to build the world’s first full-scale quantum computer,” GlobalFoundries, May 5, 2021.
2. Yifan Liu et al., “High-sensitivity SNSPD-enabled swept source Raman spectroscopy for cancer detection with SERS nanoparticles,” Optica, December 20, 2025, Volume 12, Number 12; Feifei Wang et al., “In vivo non-invasive confocal fluorescence imaging beyond 1,700 nm using superconducting nanowire single-photon detectors,” Nature Nanotechnology, June 2022, Volume 17, Number 6; Chien-Sing Poon et al., “First-in-clinical application of a time-gated diffuse correlation spectroscopy system at 1,064 nm using superconducting nanowire single photon detectors in a neuro intensive care unit,” Biomedical Optics Express, March 2022, Volume 13, Number 3.
3. Kendall Murphy, “NASA laser terminal enhances views during Artemis II mission,” NASA, April 28, 2026.
4. “Achieving HD video for Artemis II with space-to-ground lasers,” Observable Space, April 22, 2026.