This paper presents the experimental observation of a trapped light state within the radiation continuum, achieved using a patterned dielectric slab. The study demonstrates that light can be perfectly confined in a dielectric slab even when outgoing waves are allowed in the surrounding medium. This phenomenon is referred to as an "embedded eigenvalue," a bound state in the continuum of radiation modes that does not arise from symmetry incompatibility. The trapped state is stable in a general class of geometries where all radiation amplitudes vanish simultaneously due to destructive interference. The research shows that electromagnetic waves can be trapped using a photonic crystal (PhC) slab with a square array of cylindrical holes. The periodic geometry of the PhC slab leads to photonic band structures, similar to how periodic potentials in solids give rise to electron band structures. The PhC slab supports guided resonances whose frequencies lie within the continuum of radiation modes in free space. However, using finite-difference time-domain (FDTD) simulations and analytical proofs, the study finds that the lifetime of the resonance goes to infinity at discrete k points on certain bands. These states are no longer leaky resonances; they are eigenmodes that do not decay. The trapped state is robust and can persist even when the rotational symmetry of the structure is broken. The study confirms the existence of the trapped state through experimental measurements, including angle-resolved reflectivity measurements. The results show that the Fano feature of the TM1 band disappears near 35 degrees, indicating the presence of a trapped state with no leakage. The measured radiative lifetime Qr reaches 1,000,000, which is consistent with values calculated from FDTD simulations. The trapped state has a high quality factor, indicating low loss and large field enhancement, and is suitable for applications such as chemical/biological sensing, organic light emitting devices, and large-area laser applications. The study also shows that the state has wavevector and wavelength selectivity, making it suitable for optical filters, modulators, and waveguides. The fundamental principles of this state hold for any linear wave phenomenon, not just optics. The research provides a new method for trapping electromagnetic waves, applicable to electronic and mechanical waves as well.This paper presents the experimental observation of a trapped light state within the radiation continuum, achieved using a patterned dielectric slab. The study demonstrates that light can be perfectly confined in a dielectric slab even when outgoing waves are allowed in the surrounding medium. This phenomenon is referred to as an "embedded eigenvalue," a bound state in the continuum of radiation modes that does not arise from symmetry incompatibility. The trapped state is stable in a general class of geometries where all radiation amplitudes vanish simultaneously due to destructive interference. The research shows that electromagnetic waves can be trapped using a photonic crystal (PhC) slab with a square array of cylindrical holes. The periodic geometry of the PhC slab leads to photonic band structures, similar to how periodic potentials in solids give rise to electron band structures. The PhC slab supports guided resonances whose frequencies lie within the continuum of radiation modes in free space. However, using finite-difference time-domain (FDTD) simulations and analytical proofs, the study finds that the lifetime of the resonance goes to infinity at discrete k points on certain bands. These states are no longer leaky resonances; they are eigenmodes that do not decay. The trapped state is robust and can persist even when the rotational symmetry of the structure is broken. The study confirms the existence of the trapped state through experimental measurements, including angle-resolved reflectivity measurements. The results show that the Fano feature of the TM1 band disappears near 35 degrees, indicating the presence of a trapped state with no leakage. The measured radiative lifetime Qr reaches 1,000,000, which is consistent with values calculated from FDTD simulations. The trapped state has a high quality factor, indicating low loss and large field enhancement, and is suitable for applications such as chemical/biological sensing, organic light emitting devices, and large-area laser applications. The study also shows that the state has wavevector and wavelength selectivity, making it suitable for optical filters, modulators, and waveguides. The fundamental principles of this state hold for any linear wave phenomenon, not just optics. The research provides a new method for trapping electromagnetic waves, applicable to electronic and mechanical waves as well.