How to add a greek letter to an axis label to a 3D plot in plotly?

I have below plot using plotly

library(plotly)
set.seed(1)
n <- 100
theta <- runif(n, 0, 2*pi)
u <- runif(n, -1, 1)


base<-'B1'
compare<-'A1'

p <- plot_ly(x = ~sqrt(1 - u^2) * cos(theta), y = ~sqrt(1 - u^2) * sin(theta), z = ~u) %>%
  layout(
    title = "Some plot",
    scene = list(
      yaxis = list(title = expression('theta'))
    ))
p

I wanted to add greek expression theta in the y-axis title, and tried using expression(theta), however it is not rendering.

Could you please find how is it possible to add greek letters in plotly?

One option would be to use UTF-8 codes, e.g. "\u03B8" for a theta

library(plotly)
set.seed(1)

n <- 100
theta <- runif(n, 0, 2*pi)
u <- runif(n, -1, 1)

base<-'B1'
compare<-'A1'

p <- plot_ly(x = ~sqrt(1 - u^2) * cos(theta), y = ~sqrt(1 - u^2) * sin(theta), z = ~u) %>%
  layout(
    title = "Some plot",
    scene = list(
      xaxis = list(title = list(text = "\u03B8")),
      yaxis = list(title = "Y-axis")
    ))
p