This study presents experimental evidence of the quantum-optical nature of high-harmonic generation (HHG) in semiconductors. The research demonstrates that HHG can produce non-classical states of light, such as multipartite broadband entanglement and multimode squeezing, which are essential for quantum technologies. The experiments were conducted using a femtosecond infrared laser and standard semiconductors, operating at room temperature. The results show that the harmonic emission exhibits non-classical features, including two-mode squeezing and a violation of the Cauchy-Schwarz inequality, which are indicators of quantum entanglement. The study also reveals that the photon statistics of HHG depend on the laser intensity, transitioning from super-Poissonian to Poissonian statistics as the intensity increases. The findings are supported by theoretical models and highlight the potential of HHG as a quantum optical platform for applications in quantum computing, communication, and imaging. The research underscores the importance of quantum optical effects in HHG and provides insights into the generation of non-classical light states in solid-state systems.This study presents experimental evidence of the quantum-optical nature of high-harmonic generation (HHG) in semiconductors. The research demonstrates that HHG can produce non-classical states of light, such as multipartite broadband entanglement and multimode squeezing, which are essential for quantum technologies. The experiments were conducted using a femtosecond infrared laser and standard semiconductors, operating at room temperature. The results show that the harmonic emission exhibits non-classical features, including two-mode squeezing and a violation of the Cauchy-Schwarz inequality, which are indicators of quantum entanglement. The study also reveals that the photon statistics of HHG depend on the laser intensity, transitioning from super-Poissonian to Poissonian statistics as the intensity increases. The findings are supported by theoretical models and highlight the potential of HHG as a quantum optical platform for applications in quantum computing, communication, and imaging. The research underscores the importance of quantum optical effects in HHG and provides insights into the generation of non-classical light states in solid-state systems.