R：为情节标题，轴标签或图例创建拉丁语/希腊语表达的向量

I would like to merge vectors of Latin and Greek text to generate plot titles, axis labels, legend entries, etc. I have provided a trivial example below. I cannot figure out how to render the Greek letters in their native form. I have tried various combinations of I would like to merge vectors of Latin and Gree