This paper presents an experimental realization of a one-way quantum computer using a four-qubit cluster state. The cluster state is prepared through nonlinear optics and characterized using quantum state tomography. The cluster state is a highly entangled state of four photons, which serves as the resource for quantum computation. The one-way quantum computer operates by performing single-qubit measurements on the cluster state, with classical feedforward of the measurement outcomes. This approach allows for the implementation of quantum algorithms without the need for traditional quantum gates. The paper demonstrates the feasibility of one-way quantum computing by implementing a universal set of single- and two-qubit quantum logic gates. It also shows the implementation of Grover's search algorithm, which is a key example of the power of one-way quantum computation. The results show that the cluster state approach is highly efficient and can be used for quantum computing tasks that are intractable for classical computers. The one-way quantum computer is based on the entanglement properties of the cluster state. The computation proceeds by performing single-qubit measurements on the cluster state, with the outcomes of these measurements determining the sequence of operations. The cluster state is prepared using a mode- and polarization-entangled four-photon state produced through spontaneous parametric down-conversion. The cluster state is then characterized using quantum state tomography, which allows for the full reconstruction of the density matrix of the state. The paper also discusses the entanglement properties of the cluster state and shows that it can be used to implement a variety of quantum algorithms. The results demonstrate that the cluster state approach is a promising method for quantum computing, with the potential for scalable and fault-tolerant implementations. The paper concludes with a discussion of the challenges and future directions for one-way quantum computing, including the need for efficient feedforward mechanisms and the development of larger cluster states.This paper presents an experimental realization of a one-way quantum computer using a four-qubit cluster state. The cluster state is prepared through nonlinear optics and characterized using quantum state tomography. The cluster state is a highly entangled state of four photons, which serves as the resource for quantum computation. The one-way quantum computer operates by performing single-qubit measurements on the cluster state, with classical feedforward of the measurement outcomes. This approach allows for the implementation of quantum algorithms without the need for traditional quantum gates. The paper demonstrates the feasibility of one-way quantum computing by implementing a universal set of single- and two-qubit quantum logic gates. It also shows the implementation of Grover's search algorithm, which is a key example of the power of one-way quantum computation. The results show that the cluster state approach is highly efficient and can be used for quantum computing tasks that are intractable for classical computers. The one-way quantum computer is based on the entanglement properties of the cluster state. The computation proceeds by performing single-qubit measurements on the cluster state, with the outcomes of these measurements determining the sequence of operations. The cluster state is prepared using a mode- and polarization-entangled four-photon state produced through spontaneous parametric down-conversion. The cluster state is then characterized using quantum state tomography, which allows for the full reconstruction of the density matrix of the state. The paper also discusses the entanglement properties of the cluster state and shows that it can be used to implement a variety of quantum algorithms. The results demonstrate that the cluster state approach is a promising method for quantum computing, with the potential for scalable and fault-tolerant implementations. The paper concludes with a discussion of the challenges and future directions for one-way quantum computing, including the need for efficient feedforward mechanisms and the development of larger cluster states.